Publications of Ying Wu    :chronological  alphabetical  combined listing:

%% Papers Published   
@article{fds329977,
   Author = {Li, W and Hao, H and Mikhailov, SF and Popov, V and Li, W-M and Wu,
             YK},
   Title = {Compensation for booster leakage field in the Duke storage
             ring},
   Journal = {Chinese Physics C},
   Volume = {41},
   Number = {1},
   Pages = {017002-017002},
   Year = {2017},
   Month = {January},
   url = {http://dx.doi.org/10.1088/1674-1137/41/1/017002},
   Doi = {10.1088/1674-1137/41/1/017002},
   Key = {fds329977}
}

@article{fds329978,
   Author = {Li, W and Hao, H and Mikhailov, SF and Xu, W and Li, J-Y and Li, W-M and Wu,
             YK},
   Title = {Study of magnetic hysteresis effects in a storage ring using
             precision tune measurement},
   Journal = {Chinese Physics C},
   Volume = {40},
   Number = {12},
   Pages = {127002-127002},
   Year = {2016},
   Month = {December},
   url = {http://dx.doi.org/10.1088/1674-1137/40/12/127002},
   Doi = {10.1088/1674-1137/40/12/127002},
   Key = {fds329978}
}

@article{fds329979,
   Author = {Yan, J and Hao, H and Li, JY and Mikhailov, SF and Popov, VG and Vinokurov,
             NA and Huang, S and Wu, J and Günster, S and Wu, YK},
   Title = {Storage ring two-color free-electron laser},
   Journal = {Physical Review Accelerators and Beams},
   Volume = {19},
   Number = {7},
   Year = {2016},
   Month = {July},
   url = {http://dx.doi.org/10.1103/PhysRevAccelBeams.19.070701},
   Doi = {10.1103/PhysRevAccelBeams.19.070701},
   Key = {fds329979}
}

@article{fds329980,
   Author = {Li, W and Hao, H and Xu, W and Li, W and Wu, YK},
   Title = {Direct and high resolution beta-function measurements for
             storage ring lattice characterization},
   Journal = {IPAC 2016 - Proceedings of the 7th International Particle
             Accelerator Conference},
   Pages = {3272-3274},
   Year = {2016},
   Month = {January},
   ISBN = {9783954501472},
   Abstract = {Copyright © 2016 CC-BY-3.0 and by the respective authors.
             Betatron functions are a set of commonly used merits to
             characterize the lattice performance of a circular
             accelerator. The betatron functions in many accelerators can
             be computed using a lattice model trained or calibrated
             using a set of closed orbit responses, which is exemplified
             by the widely used Linear Optics from Closed Orbit (LOCO)
             technique. However, for some accelerators, like Duke storage
             ring with quad-sextupole combined function magnets, LOCO
             cannot be employed in any straight forward manner. In this
             case, direct measurements for betatron function are
             required. One way to determine betatron functions at the
             location of quadrupoles for a circular accelerator is to use
             the relationship between the quadrupole strength variations
             and the corresponding betatron tune change. In this paper,
             we present a set of carefully developed techniques to
             measure the betatron functions at the location of
             quadrupoles, which allow us to achieve extremely high
             resolution. Measurement errors will be discussed, and the
             detailed measurement technique will be present. Finally, the
             experimental results of betatron function measurements in
             the Duke storage ring with statistical error on the order of
             1% will be presented.},
   Key = {fds329980}
}

@article{fds292654,
   Author = {Laskaris, G and Yan, X and Mueller, JM and Zimmerman, WR and Xiong, W and Ahmed, MW and Averett, T and Chu, P-H and Deltuva, A and Flower, C and Fonseca, AC and Gao, H and Golak, J and Heideman, JN and Karwowski, HJ and Meziane, M and Sauer, PU and Skibiński, R and Strakovsky, II and Weller, HR and Witała, H and Wu, YK},
   Title = {Measurement of the doubly-polarized reaction at 16.5 MeV and
             its implications for the GDH sum rule},
   Journal = {Physics Letters B},
   Volume = {750},
   Pages = {547-551},
   Year = {2015},
   Month = {November},
   ISSN = {0370-2693},
   url = {http://dx.doi.org/10.1016/j.physletb.2015.09.065},
   Abstract = {© 2015 The Authors.We report new measurements of the
             double-polarized photodisintegration of 3He at an incident
             photon energy of 16.5 MeV, carried out at the High Intensity
             γ-ray Source (HIγS) facility located at Triangle
             Universities Nuclear Laboratory (TUNL). The spin-dependent
             double-differential cross sections and the contribution from
             the three-body channel to the Gerasimov-Drell-Hearn (GDH)
             integrand were extracted and compared with the
             state-of-the-art three-body calculations. The calculations,
             which include the Coulomb interaction and are in good
             agreement with the results of previous measurements at 12.8
             and 14.7 MeV, deviate from the new cross section results at
             16.5 MeV. The GDH integrand was found to be about one
             standard deviation larger than the maximum value predicted
             by the theories.},
   Doi = {10.1016/j.physletb.2015.09.065},
   Key = {fds292654}
}

@article{fds292653,
   Author = {Wu, YK and Yan, J and Hao, H and Li, JY and Mikhailov, SF and Popov, VG and Vinokurov, NA and Huang, S and Wu, J},
   Title = {Widely Tunable Two-Color Free-Electron Laser on a Storage
             Ring.},
   Journal = {Physical Review Letters},
   Volume = {115},
   Number = {18},
   Pages = {184801},
   Year = {2015},
   Month = {October},
   ISSN = {0031-9007},
   url = {http://dx.doi.org/10.1103/physrevlett.115.184801},
   Abstract = {With a wide wavelength tuning range, free-electron lasers
             (FELs) are well suited for producing simultaneous lasing at
             multiple wavelengths. We present the first experimental
             results of a novel two-color storage ring FEL. With three
             undulators and a pair of dual-band mirrors, the two-color
             FEL can lase simultaneously in infrared (IR) around 720 nm
             and in ultraviolet (UV) around 360 nm. We have demonstrated
             independent wavelength tuning in a wide range (60 nm in IR
             and 24 nm in UV). We have also realized two-color harmonic
             operation with the UV lasing tuned to the second harmonic of
             the IR lasing. Furthermore, we have demonstrated good power
             stability with two-color lasing, and good control of the
             power sharing between the two colors.},
   Doi = {10.1103/physrevlett.115.184801},
   Key = {fds292653}
}

@article{fds249241,
   Author = {Weller, HR and Ahmed, MW and Wu, YK},
   Title = {Nuclear Physics Research at the High Intensity Gamma-Ray
             Source (HIγS)},
   Journal = {Nuclear Physics News},
   Volume = {25},
   Number = {3},
   Pages = {19-24},
   Year = {2015},
   Month = {July},
   ISSN = {1061-9127},
   url = {http://dx.doi.org/10.1080/10619127.2015.1035932},
   Doi = {10.1080/10619127.2015.1035932},
   Key = {fds249241}
}

@article{fds320333,
   Author = {Li, W and Li, J and Hao, H and Mikhailov, SF and Popov, V and Wu,
             YK},
   Title = {Measuring Duke storage ring lattice using tune based
             technique},
   Journal = {6th International Particle Accelerator Conference, IPAC
             2015},
   Pages = {293-296},
   Year = {2015},
   Month = {January},
   ISBN = {9783954501687},
   Abstract = {Copyright © 2015 CC-BY-3.0 and by the respective authors.
             The Duke electron storage ring is a dedicated driver for
             oscillator Free-Electron Lasers (FELs). A 34 m long straight
             section of the storage ring is used to host up to four FEL
             wigglers in several different configurations. A total of six
             wigglers, two planar OK-4 wigglers and four helical OK-5
             wigglers, are available for FEL research. The storage ring
             magnetic lattice has to be designed with great flexibility
             to enable the storage ring operation with different FEL
             wigglers, at various wiggler settings, and for different
             electron beam energies. Since 2012, the storage ring has
             demonstrated all designed characteristics in terms of
             lattice flexibility and tuning. This work is aimed at
             gaining better understanding of the real storage ring
             lattice by performing a series of measurements of the
             beta-functions along the storage ring. Unlike the LOCO
             technique, the β-functions in the quadrupoles are directly
             measured with good accuracy using a tune measurement system.
             We will describe our experimental design and techniques, and
             measurement procedures. We will also report our preliminary
             results for the lattice characterization.},
   Key = {fds320333}
}

@article{fds320334,
   Author = {Wu, YK},
   Title = {Light source and accelerator physics research program at
             Duke university},
   Journal = {6th International Particle Accelerator Conference, IPAC
             2015},
   Pages = {1866-1868},
   Year = {2015},
   Month = {January},
   ISBN = {9783954501687},
   Abstract = {Copyright © 2015 CC-BY-3.0 and by the respective authors.
             The light source and accelerator physics research program at
             Duke Free-Electron Laser Laboratory (DFELL), Triangle
             Universities Nuclear Laboratory, is focused on the
             development of the storage ring based free-electron lasers
             (FELs), and an FEL driven state-of-the-art Compton gamma-ray
             source, the High Intensity Gamma-ray Source (HIGS). With a
             maximum total flux about 3 × 10 10 γ/s and a spectral flux
             of more than 10 3 γ/s/eV around 10 MeV, the HIGS is the
             world's most intense Compton gamma-ray source. Operated in
             the energy range from 1 to 100 MeV, the HIGS is a premier
             Compton gamma-ray facility in the world for a variety of
             nuclear physics research programs, both fundamental and
             applied. In this paper, we will describe our ongoing
             accelerator physics and light source development program in
             the areas of the storage ring magnetic optics
             characterization and compensation, FEL physics, and
             development of gamma-ray beams in the higher energy range
             (100 to 158 MeV).},
   Key = {fds320334}
}

@article{fds320335,
   Author = {Mikhailov, SF and Hao, H and Popov, VG and Wu, YK},
   Title = {Developing an improved pulsed mode operation for Duke
             storage ring based FEL},
   Journal = {6th International Particle Accelerator Conference, IPAC
             2015},
   Pages = {1860-1862},
   Year = {2015},
   Month = {January},
   ISBN = {9783954501687},
   Abstract = {Copyright © 2015 CC-BY-3.0 and by the respective authors.
             The Duke FEL and High Intensity Gamma-ray Source (HIGS)
             facility is operated with an e-beam from 0.24 to 1.2 GeV and
             a photon beam from 190 to 1060 nm. Currently, the energy
             range of the gamma-ray beam is from 1 MeV to about 100 MeV,
             with the maximum total gamma-ray flux about 3E10 gammas per
             second around 10 MeV. The FEL is typically operated in
             quasi-CW mode. Some HIGS user experiments can benefit
             tremendously from a pulsed mode of FEL operation. For that
             purpose, a fast steering magnet was developed years ago [1]
             to modulate the FEL gain. This allows a build-up of a high
             peak power FEL pulse from a well-damped electron beam.
             However, the use of this gain modulator at low e-beam
             energies can dramatically limit e-beam current due to beam
             instability and poor injection. It also suffers from the
             problem of a significantly reduced ebeam lifetime. To
             overcome these shortcomings, we developed and successfully
             tested an RF frequency modulation technique to pulse the FEL
             beam. In this paper, we will describe this development, and
             report our preliminary results of this improved pulsed FEL
             operation.},
   Key = {fds320335}
}

@article{fds320336,
   Author = {Wallace, PW and Emamian, M and Hao, H and Mikhailov, SF and Popov, V and Wu, YK and Li, J},
   Title = {Extending ok5 wiggler operational limit at duke fel/higs
             facility},
   Journal = {6th International Particle Accelerator Conference, IPAC
             2015},
   Pages = {1863-1865},
   Year = {2015},
   Month = {January},
   ISBN = {9783954501687},
   Abstract = {Copyright © 2015 CC-BY-3.0 and by the respective authors.
             Since 2007 the HIGS facility has been operated to produce
             both linearly and circularly polarized gamma-ray beams using
             two FELs, the planar OK-4 FEL and helical OK-5 FEL.
             Presently, with the OK-5 FEL operating at 192 nm, we can
             produce circularly-polarized gamma-ray beams between 1 and
             100 MeV for user applications. Gamma-ray production between
             80 and 100 MeV required an extension of the OK-5 wiggler
             operation beyond the designed current limit of 3.0 kA. In
             2009, we upgraded cooling and machine protection systems to
             successfully extend OK-5 operation to 3.5 kA. To realize
             HIGS gamma-ray operation beyond 100 MeV and ultimately
             toward 150 MeV (the pion-threshold energy), with various
             limitations of the VUV mirror technology, the OK-5 wigglers
             will need to be operated at an even higher current, between
             3.6 and 4.0 kA. In this paper we present our technical
             solution to further extend the operation range of the OK-5
             wigglers, and report our preliminary results with
             high-current wiggler operation.},
   Key = {fds320336}
}

@article{fds320337,
   Author = {Yan, J and Wu, YK and Mikhailov, S and Hao, H and Popov, V and Li, J and Wu,
             J and Vinokurov, NA and Huang, S},
   Title = {Experimental study of a two-color storage ring FEL
             ?},
   Journal = {6th International Particle Accelerator Conference, IPAC
             2015},
   Pages = {1198-1200},
   Year = {2015},
   Month = {January},
   ISBN = {9783954501687},
   Abstract = {Copyright © 2015 CC-BY-3.0 and by the respective authors.
             Multi-color Free-electron Lasers (FELs) have been developed
             on linac based FELs over the past two decades. On the
             storage ring, the optical klystron (OK) FEL in its early
             days was demonstrated to produce lasing at two adjacent
             wavelengths with their spectral separation limited by the
             bandwidth of single wiggler radiation. Here, we report a
             systematic experimental study on the two-color operation at
             the Duke FEL facility, the first experimental demonstration
             of a tunable two-color harmonic FEL operation of a storage
             ring based FEL. We demonstrate a simultaneous generation of
             two FEL wavelengths, one in infrared (IR) and the other in
             ultraviolet (UV) with a harmonic relationship. The
             experimental results show a good performance of the
             two-color FEL operation in terms of two-color wavelength
             tunability, power tunability and power stability.},
   Key = {fds320337}
}

@article{fds320338,
   Author = {Hao, H and Mikhailov, S and Popov, V and Wu, YK and Li,
             J},
   Title = {Characterizing betatron tune knobs at Duke storage
             ring},
   Journal = {6th International Particle Accelerator Conference, IPAC
             2015},
   Pages = {672-674},
   Year = {2015},
   Month = {January},
   ISBN = {9783954501687},
   Abstract = {Copyright © 2015 CC-BY-3.0 and by the respective authors. A
             good control of the electron beam betatron tune is critical
             for the operation of a storage ring. As the driver for Duke
             free-electron lasers (FELs) and the High Intensity Gammaray
             Source (HIGS), the Duke storage ring is operated in a wide
             energy range (0.3 GeV - 1.2 GeV), with several different
             electromagnetic wiggler configurations. This creates the
             challenge of controlling the betatron tune in a global
             manner. As the the first step, the feedforward tune
             compensation schemes were designed and implemented to the
             real-time computer control system to compensate the tune
             change caused by the wiggler field. To further increase the
             flexibility of the operation, a set of tune knob schemes are
             designed for various wiggler configurations. The β function
             changes caused by these knobs are constrained within the
             south straight section where the tune knob is located,
             minimizing the impact on the electron beam dynamics (i.e.
             injection and lifetime). The tune and β function
             measurements show a good agreement with the calculation. In
             addition, it is found that some tune knob schemes are
             effective for new wiggler configurations that are not
             originally designed for.},
   Key = {fds320338}
}

@article{fds249242,
   Author = {Xu, W and Li, J-Y and Huang, S-L and Wu, WZ and Hao, H and Wang, P and Wu,
             YK},
   Title = {Conditioning of BPM pickup signals for operations of the
             Duke storage ring with a wide range of single-bunch
             current},
   Journal = {Chinese Physics C},
   Volume = {38},
   Number = {10},
   Pages = {107003-107003},
   Year = {2014},
   Month = {October},
   ISSN = {1674-1137},
   url = {http://dx.doi.org/10.1088/1674-1137/38/10/107003},
   Doi = {10.1088/1674-1137/38/10/107003},
   Key = {fds249242}
}

@article{fds249244,
   Author = {Huang, S and Li, JY and Jia, B and Wu, YK},
   Title = {Relative spectral response measurement of spectrometers
             using undulator radiation},
   Journal = {Journal of Instrumentation},
   Volume = {9},
   Number = {03},
   Pages = {P03002-P03002},
   Year = {2014},
   Month = {March},
   url = {http://dx.doi.org/10.1088/1748-0221/9/03/P03002},
   Doi = {10.1088/1748-0221/9/03/P03002},
   Key = {fds249244}
}

@article{fds249245,
   Author = {Laskaris, G and Ye, Q and Lalremruata, B and Ye, QJ and Ahmed, MW and Averett, T and Deltuva, A and Dutta, D and Fonseca, AC and Gao, H and Golak, J and Huang, M and Karwowski, HJ and Mueller, JM and Myers, LS and Peng, C and Perdue, BA and Qian, X and Sauer, PU and Skibiński, R and Stave, S and Tompkins, JR and Weller, HR and Witała, H and Wu, YK and Zhang, Y and Zheng, W},
   Title = {Spin-dependent cross sections from the three-body
             photodisintegration of at incident energies of 12.8 and 14.7
             MeV},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {89},
   Number = {2},
   Year = {2014},
   Month = {February},
   ISSN = {0556-2813},
   url = {http://dx.doi.org/10.1103/PhysRevC.89.024002},
   Doi = {10.1103/PhysRevC.89.024002},
   Key = {fds249245}
}

@article{fds249246,
   Author = {Wu, YK},
   Title = {Accelerator physics and light source research program at
             duke university},
   Journal = {IPAC 2013: Proceedings of the 4th International Particle
             Accelerator Conference},
   Pages = {264-266},
   Year = {2013},
   Month = {December},
   Abstract = {The accelerator physics and light source research program at
             the Duke Free-Electron Laser Laboratory, Triangle
             Universities Nuclear Laboratory, is focused on the
             development of the storage ring based free-electron lasers
             (FELs), and a state-of-the-art Compton gamma-ray source, the
             High Intensity Gamma-ray Source (HIGS). Driven by the
             storage ring FEL, the HIGS is the world's most intense
             Compton gamma-ray source with a maximum total flux of a few
             1010 γ/s (around 10 MeV). Operated in the energy range from
             1 to 100 MeV, the HIGS is a premier nuclear physics research
             facility in the world. In 2012, we completed a major
             accelerator upgrade project with the installation of a
             wiggler switchyard system which allows changeovers between
             two planar and two helical FEL wigglers in the middle of the
             FEL section. In this paper, we report the light source R & D
             activities related to the wiggler switchyard project and VUV
             FEL lasing, and provide a summary of the accelerator physics
             research program at the laboratory. Copyright © 2013 by
             JACoW.},
   Key = {fds249246}
}

@article{fds249247,
   Author = {Hao, H and Mikhailov, SF and Li, J and Wu, YK},
   Title = {Design of a soft orbit bump for FEL mirror protection at
             duke FEL/HIGS facility},
   Journal = {IPAC 2013: Proceedings of the 4th International Particle
             Accelerator Conference},
   Pages = {2006-2008},
   Year = {2013},
   Month = {December},
   Abstract = {In an oscillator Free-Electron Laser (FEL) with a high
             energy electron beam, it is critical to minimize harmful
             high-energy radiation on the downstream FEL mirror in order
             to increase its lifetime. At the High Intensity Gammaray
             Source (HIGS) facility at Duke University, effort has been
             devoted to developing a variety of techniques to reduce the
             amount of radiation on the FEL mirror. One of the most
             effective methods was the use of a set of adjustable
             in-vacuum apertures to block harmonic radiation from FEL
             wigglers. In recent studies, it was determined that the edge
             radiation from the end-of-the-arc bending magnet is a main
             source of EUV and soft x-ray radiation which causes mirror
             damage. To mitigate this effect, a soft orbit bump is
             designed to change the displacement and angle of the
             electron beam around the end-of-the-arc area. This soft
             orbit bump is developed using the multi-objective
             optimization technique. Calculation shows the soft orbit
             bump can significantly reduce the flux of high energy
             photons on the FEL mirror. Study will be performed to
             determine the impact of this orbit bump on the injection,
             beam lifetime, and the FEL and gamma-ray operation at HIGS
             facility. Copyright © 2013 by JACoW.},
   Key = {fds249247}
}

@article{fds249248,
   Author = {Mikhailov, SF and Hao, H and Li, JY and Popov, VG and Wallace, PW and Wu,
             YK},
   Title = {Protection of VUV FEL mirrors using soft orbit bump at duke
             FEL / HIγS facility},
   Journal = {IPAC 2013: Proceedings of the 4th International Particle
             Accelerator Conference},
   Pages = {1301-1303},
   Year = {2013},
   Month = {December},
   Abstract = {The Duke FEL and High Intensity Gamma-ray Source (HIγS)
             facility is operated with an electron beam from 0.24 to 1.2
             GeV and a photon beam from 190 to 1060 nm. Presently, the
             energy range of the gamma-beam is from 1 MeV to about 100
             MeV, with the maximum total gamma-flux of more then 10 10
             gammas per second around 10 MeV. Production of high
             intensity, high energy gamma-beams of 60 to 100 MeV, using
             UV-VUV mirrors of 240 to 190 nm, requires high energy, high
             current electron beams of 0.9 to 1.05 GeV. Synchrotron
             radiation damage to the FEL mirrors becomes crucial for VUV
             FEL operation at or below 190 nm. The edge radiation (ER)
             from the End-of-Arc (EOA) bending magnet, instead of the
             radiation of FEL wigglers, is the dominant cause of rapid
             degradation of the downstream FEL mirror. We describe here a
             further development of the "soft" orbit bump concept to
             significantly reduce the radiation exposure to the mirror
             from the EOA dipole magnet. The bump uses designated "soft"
             orbit correctors with magnetic field limited to produce
             radiation with a critical wavelength close to or longer than
             the FEL wavelength. A first experience of HIγS user runs
             with 192 nm mirrors utilizing the soft bump is also
             presented. Copyright © 2013 by JACoW.},
   Key = {fds249248}
}

@article{fds249249,
   Author = {Li, JY and Hao, H and Wu, WZ and Mikhailov, S and Popov, V and Wu,
             YK},
   Title = {Compensation schemes for operation of FEL wigglers on duke
             storage ring},
   Journal = {IPAC 2013: Proceedings of the 4th International Particle
             Accelerator Conference},
   Pages = {3270-3272},
   Year = {2013},
   Month = {December},
   Abstract = {The Duke Free-electron laser is the photon driver for the
             High Intensity Gamma-ray Source (HIGS). To extend the
             capabilities of the FEL and HIGS to higher photon energy
             regions, an FEL wiggler switchyard system was developed in
             the recent years. This system was installed and commissioned
             in 2012. The FEL wiggler switchyard is used to change
             between two planar OK-4 wigglers and two helical OK-5
             wigglers in the middle of the FEL straight section in a
             short period of time (a few days). With a total number of
             six electromagnetic wigglers, the Duke FEL can be operated
             in a number of wiggler configurations and with a wide range
             of magnetic fields. The operation of uncompensated FEL
             wigglers can cause significant changes to the electron beam
             closed orbit and magnetic lattice. To maintain sufficiently
             large dynamic aperture for efficient injection and good beam
             lifetime, a set of complex compensation schemes, including
             wiggler magnetic field and lattice compensation, have been
             developed for the operation of the FEL wigglers. This paper
             reports the overall architecture and performance of the FEL
             wiggler compensation schemes and their implementation in the
             accelerator control system using the feed-forward
             mechanism.},
   Key = {fds249249}
}

@article{fds249250,
   Author = {Wu, YK and Hao, H and Li, J and Mikhailov, S and Popov, V and Wu, WZ and Yan,
             J and Emamian, M and Busch, M and Faircloth, J and Swift, G and Wallace, P and Wang, P},
   Title = {Commissioning and operation of wiggler switchyard system for
             duke FEL and HIGS},
   Journal = {IPAC 2013: Proceedings of the 4th International Particle
             Accelerator Conference},
   Pages = {267-269},
   Year = {2013},
   Month = {December},
   Abstract = {To enable the Duke storage ring FEL to operate in VUV with
             adequate gain, a major storage ring upgrade was carried out
             in 2012 to install two additional helical FEL wigglers with
             a wiggler switchyard system. Using the switchyard, a quick
             changeover can be made between two planar OK-4 wigglers and
             two helical OK-5 wigglers in the middle of the FEL straight
             section. This system preserves the linear polarization
             capabilities of the Duke FEL and High Intensity Gamma-ray
             Source (HIGS), while enabling VUV FEL operation with a
             higher gain using a longer FEL with up to four helical
             wigglers. The switchyard upgrade was completed in Summer
             2012, followed by a rapid and successful commissioning of
             the Duke storage ring, FEL system, and HIGS. In this paper,
             we describe the development of the wiggler switchyard, its
             installation and commissioning, and its impact on the
             research program at the HIGS. Copyright © 2013 by
             JACoW.},
   Key = {fds249250}
}

@article{fds249263,
   Author = {Laskaris, G and Ye, Q and Lalremruata, B and Ye, QJ and Ahmed, MW and Averett, T and Deltuva, A and Dutta, D and Fonseca, AC and Gao, H and Golak, J and Huang, M and Karwowski, HJ and Mueller, JM and Myers, LS and Peng, C and Perdue, BA and Qian, X and Sauer, PU and Skibinski, R and Stave, S and Tompkins, JR and Weller, HR and Witala, H and Wu, YK and Zhang, Y and Zheng, W},
   Title = {First Measurements of Spin-Dependent Double-Differential
             Cross Sections and the Gerasimov-Drell-Hearn Integrand from
             (3)(H)over-right-arrowe((gamma)over-right-arrow, n)pp at
             Incident Photon Energies of 12.8 and 14.7
             MeV},
   Journal = {Physical Review Letters},
   Volume = {110},
   Number = {20},
   Pages = {152502},
   Year = {2013},
   Month = {May},
   ISSN = {0031-9007},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000319214800002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Doi = {10.1103/PhysRevLett.110.202501},
   Key = {fds249263}
}

@article{fds303764,
   Author = {Leviner, LE and Aalseth, CE and Ahmed, MW and III, FTA and Back, HO and Barabash, AS and Boswell, M and Braeckeleer, LD and Brudanin, VB and Chan, Y-D and Egorov, VG and Elliott, SR and Gehman, VM and Hossbach,
             TW and Kephart, JD and Kidd, MF and Konovalov, SI and Lesko, KT and Li, J and Mei, D-M and Mikhailov, S and Miley, H and Radford, DC and Reeves, J and Sandukovsky, VG and Umatov, VI and Underwood, TA and Tornow, W and Wu,
             YK and Young, AR},
   Title = {A Segmented, Enriched N-type Germanium Detector for
             Neutrinoless Double Beta-Decay Experiments},
   Year = {2013},
   Month = {April},
   url = {http://arxiv.org/abs/1304.5477v1},
   Abstract = {We present data characterizing the performance of the first
             segmented, N-type Ge detector, isotopically enriched to 85%
             $^{76}$Ge. This detector, based on the Ortec PT6x2 design
             and referred to as SEGA (Segmented, Enriched Germanium
             Assembly), was developed as a possible prototype for
             neutrinoless double beta-decay measurements by the {\sc
             Majorana} collaboration. We present some of the general
             characteristics (including bias potential, efficiency,
             leakage current, and integral cross-talk) for this detector
             in its temporary cryostat. We also present an analysis of
             the resolution of the detector, and demonstrate that for all
             but two segments there is at least one channel that reaches
             the {\sc Majorana} resolution goal below 4 keV FWHM at 2039
             keV, and all channels are below 4.5 keV FWHM.},
   Doi = {10.1016/j.nima.2013.08.081},
   Key = {fds303764}
}

@article{fds249264,
   Author = {Zimmerman, WR and Ahmed, MW and Bromberger, B and Stave, SC and Breskin,
             A and Dangendorf, V and Delbar, T and Gai, M and Henshaw, SS and Mueller,
             JM and Sun, C and Tittelmeier, K and Weller, HR and Wu,
             YK},
   Title = {Unambiguous Identification of the Second 2(+) State in C-12
             and the Structure of the Hoyle State},
   Journal = {Physical Review Letters},
   Volume = {110},
   Number = {15},
   Pages = {152502},
   Year = {2013},
   Month = {April},
   ISSN = {0031-9007},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000317459300008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {The second J ¼ 2þ state of 12C, predicted over 50 years
             ago as an excitation of the Hoyle state, has been
             unambiguously identified using the 12Cð;0 Þ8Be reaction.
             The alpha particles produced by the photodisintegration of
             12C were detected using an optical time projection chamber.
             Data were collected at beam energies between 9.1 and 10.7
             MeVusing the intense nearly monoenergetic gamma-ray beams at
             the HIS facility. The measured angular distributions
             determine the cross section and the E1-E2 relative phases as
             a function of energy leading to an unambiguous
             identification of the second 2þ state in 12C at 10.03(11)
             MeV, with a total width of 800(130) keVand a ground state
             gamma-decay width of 60(10) meV; BðE2 : 2þ 2 ! 0þ 1 Þ ¼
             0:73ð13Þe2 fm4 [or 0.45(8) W.u.]. The Hoyle state and its
             rotational 2þ state that are more extended than the ground
             state of 12C presents a challenge and constraints for models
             attempting to reveal the nature of three alpha-particle
             states in 12C. Specifically, it challenges the ab initio
             lattice effective field theory calculations that predict
             similar rms radii for the ground state and the Hoyle
             state.},
   Doi = {10.1103/PhysRevLett.110.152502},
   Key = {fds249264}
}

@article{fds217448,
   Author = {Stepan F. Mikhailov and Hao Hao and Jingyi Li and Victor Popov and Patrick Walter Wallace and Y.K. Wu},
   Title = {`Protection of VUV FEL Mirrors using Soft Orbit Bump at Duke
             FEL/HIGS facility},
   Journal = {Proceedings of the 2013 International Particle Accelerator
             Conference (IPAC'13), Shanghai, China, May 12 -- 17,
             2013},
   Pages = {1301 -- 1303},
   Year = {2013},
   Key = {fds217448}
}

@article{fds249243,
   Author = {Omer, M and Negm, H and Zen, H and Hori, T and Kii, T and Masuda, K and Ohgaki, H and Hajima, R and Hayakawa, T and Daito, and Shizuma, T and Fujiwara, M and Park, SH and Kikuzawa, N and Rusev, G and Tonchev, AP and Wu, YK},
   Title = {Active Interrogation of Nuclear Materials Using LaBr3: Ce
             Detectors},
   Journal = {Energy Procedia},
   Volume = {34},
   Pages = {50-56},
   Year = {2013},
   ISSN = {1876-6102},
   url = {http://dx.doi.org/10.1016/j.egypro.2013.06.732},
   Doi = {10.1016/j.egypro.2013.06.732},
   Key = {fds249243}
}

@article{fds249255,
   Author = {Popov, V and Mikhailov, S and Wallace, P and Wu, Y},
   Title = {Cold cathode thyratron based high-voltage kicker generators
             at the duke accelerators: Six year experience},
   Journal = {IPAC 2012 - International Particle Accelerator Conference
             2012},
   Pages = {3698-3700},
   Year = {2012},
   Month = {December},
   Abstract = {The performance of the Duke storage ring based light
             sources, the Duke storage ring FEL and High Intensity
             Gamma-ray Source (HIGS), has been greatly improved since
             2007 as the result of operating a new full-energy, top-off
             booster injector (0.18 - 1.2 GeV) [1], allowing fixed energy
             operation of the storage ring (0.25 - 1.2 GeV). The
             injection/extraction kicker system is one of the key
             components of the accelerator facility which determines
             efficiency and reliability of the light source operation.
             Pseudo-Spark Switches (PSS), also known as cold cathode
             thyratrons, are the critical components of the high voltage
             pulse generators for kickers. More than six years of
             operation has allowed us to study the lifetime issue for the
             10 kA class devices. Recently, we have tested the next
             generation cold cathode thyratron, with one installed in our
             storage ring kicker high voltage generators. In the paper we
             present preliminary test results for this new thyratron, and
             the required modifications of its triggering driver, to
             improve its performance. Copyright © 2012 by
             IEEE.},
   Key = {fds249255}
}

@article{fds249256,
   Author = {Hao, H and Li, J and Wu, YK},
   Title = {New storage ring lattice for the duke fel wiggler switchyard
             system},
   Journal = {IPAC 2012 - International Particle Accelerator Conference
             2012},
   Pages = {1272-1274},
   Year = {2012},
   Month = {December},
   Abstract = {The Duke storage ring is a dedicated driver for the OK- 4
             FEL and OK-5 FEL, and forthe state-of-the-art Compton
             gamma-ray source, High Intensity Gamma-Ray Source (HIGS).
             Toproduce FEL lasing below 190 nm and gammaray beams above
             100 MeV, the FEL system needs tobe upgraded to increase the
             FEL gain by adding two more helical OK-5 wigglers to form
             afour-wiggler FEL. To preserve the linear polarization
             capability of the gamma-ray beamproduced by the planar OK-4
             FEL, a wiggler switchyard system is under development
             whichwill enable the switch between two planar OK-4 wigglers
             and two helical OK-5 wigglers inthe middle of the FEL
             straight. In this work, we present the new magnetic lattice
             designedfor the operation of the wiggler switchyard system.
             This new lattice is developed withgreat flexibility for the
             operation with different numbers of FEL wigglers,
             variablebetatron tunes, and adjustable electron beam sizes
             at the collision point for the HIGS. Inaddition, the new
             lattice is developed for the operation in a wide range of
             energies, from240 MeV to 1.2 GeV, with proper nonlinear
             dynamics compensations in order to realize alarge dynamic
             aperture. Copyright © 2012 by IEEE.},
   Key = {fds249256}
}

@article{fds249257,
   Author = {Mikhailov, SF and Li, JY and Popov, VG and Wallace, PW and Wu,
             YK},
   Title = {Soft orbit bump for duke storage ring VUV FEL
             operation},
   Journal = {IPAC 2012 - International Particle Accelerator Conference
             2012},
   Pages = {1774-1776},
   Year = {2012},
   Month = {December},
   Abstract = {The Duke FEL and High Intensity Gamma-ray Source (HIS)
             facility is operated with anelectron beam from 0.24 to 1.2
             GeV and an FEL photon beam from 190 to 1060 nm. The
             energyrange of the gamma-ray beam is from 1 MeV to about 100
             MeV, with the maximum totalgamma-flux of more then 1010
             gammas per second around 10 MeV. Production of
             thehigh-intensity, high energy gamma-beams of 60-158 MeV
             using UV-VUV mirrors of 250 - 150 nmrequires high current
             and high energy electron beams (0.9-1.20 GeV). Radiation
             damage tothe downstream FEL mirror becomes more severe for
             VUV FEL operation at 190 nm and below. Atthese VUV
             wavelengths with GeV electrons, the radiation from the
             end-of-arc (EOA) bendingmagnets, instead of the radiation
             from helical FEL wigglers, is the dominant cause of arapid
             degradation of the downstream mirror. In this work, we
             propose a concept of a"soft" orbit bump using designated
             orbit correctors to significantly reduce theradiation from
             the EOA dipole toward the FEL mirror. The strength of
             magnetic field ofthese correctors is limited to produce a
             radiation with a critical wavelength close orbelow the FEL
             wavelength. Copyright © 2012 by IEEE.},
   Key = {fds249257}
}

@article{fds249258,
   Author = {Xu, W and He, D and Wu, WZ and Li, J and Wu, YK},
   Title = {Electron beam diagnostics based on transverse feedback
             system at duke storage ring},
   Journal = {IPAC 2012 - International Particle Accelerator Conference
             2012},
   Pages = {849-851},
   Year = {2012},
   Month = {December},
   Abstract = {To combat electron beam instabilities, a field programmable
             gate array (FPGA) based bunch-by-bunch transverse feedback
             (TFB) has been developed for the Duke storage ring. While it
             is capable of suppressing transverse beam instabilities for
             multi-bunch operation, the TFB system has not been needed
             for typical operation of the Duke storage ring FEL. To
             explore the great potential of this system, we have focused
             on the development of TFB based beam diagnostics. A TFB
             based tune measurement system has been developed using two
             methods: the tune scan method and tune monitoring method.
             With the tune monitoring method, a much faster method of the
             two, we have studied the tune stability of the electron beam
             in the Duke storage ring. This tune measurement system also
             allows us to conduct chromaticity measurements more quickly,
             compared with the existing chromaticity measurement system
             using a network analyzer. Finally, the TFB based tune system
             has been used to calibrate the tune knob and chromaticity
             knob for the Duke storage ring. Copyright © 2012 by
             IEEE.},
   Key = {fds249258}
}

@article{fds249262,
   Author = {Omer, M and Negm, H and Zen, H and Hori, T and Kii, T and Masuda, K and Ohgaki, H and Hajima, R and Hayakawa, T and Daito, I and Shizuma, T and Fujiwara, M and Park, SH and Kikuzawa, N and Rusev, G and Tonchev, AP and Wu, YK},
   Title = {Detection of photon-induced excitations in 235U
             with LaBr 3:Ce scintillating detectors},
   Journal = {IEEE Nuclear Science Symposium Conference
             Record},
   Pages = {55-58},
   Year = {2012},
   ISSN = {1095-7863},
   url = {http://dx.doi.org/10.1109/NSSMIC.2012.6551059},
   Abstract = {Excitations in 235U were measured with LaBr3:Ce
             scintillation detectors using the nuclear resonance
             fluorescence (NRF) technique. A NRF experiment was performed
             at the High Intensity γ-ray Source (HIγS) facility using
             quasi-monochromatic circularly or linearly polarized γ-ray
             beams. Photons scattered at 90°relative to the incident
             beam were detected with two different sizes of cylindrical
             LaBr 3:Ce detectors. Clear NRF peaks at 1733 and 1815 keV
             corresponding to de-excitations to the ground state and/or
             low-lying levels in 235U were observed within 77 minutes of
             beam time even under the high background due to the
             self-activity of LaBr3:Ce and the radioactive decay of 214Bi
             nuclei existing in the 235U target. The present study shows
             a possibility of using LaBr3:Ce detector to perform NRF
             experiments, promoting many options for inspection of
             special nuclear materials. © 2012 IEEE.},
   Doi = {10.1109/NSSMIC.2012.6551059},
   Key = {fds249262}
}

@article{fds249337,
   Author = {Wei, X and Wu, WZ and Li, JY and Due-Hui, H and Wu, YK},
   Title = {Betatron Tune Measurement System Based on Bunch-by-bunch
             Transverse Feedback at Duke Storage Ring},
   Journal = {Chinese Phys. C},
   Volume = {37},
   Pages = {077006},
   Year = {2012},
   Key = {fds249337}
}

@article{fds249338,
   Author = {Wei, X and Wu, WZ and Due-Hui, H and Wu, YK},
   Title = {Design and Optimization of Longitudinal Feedback Kicker
             Cavity for HLS-II Storage Ring},
   Journal = {Chinese Phys. C},
   Volume = {37},
   Pages = {037003},
   Year = {2012},
   Key = {fds249338}
}

@article{fds249328,
   Author = {Wu, WZ and Kim, Y and Li, JY and Teytelman, D and Busch, M and Wang, P and Swift, G and Park, IS and Ko, IS and Wu, YK},
   Title = {Development of a bunch-by-bunch longitudinal feedback system
             with a wide dynamic range for the HIGS facility},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {632},
   Number = {1},
   Pages = {32-42},
   Year = {2011},
   Month = {March},
   ISSN = {0168-9002},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000288049000005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {Electron beam coupled-bunch instabilities can limit and
             degrade the performance of storage ring based light sources.
             A longitudinal feedback system has been developed for the
             Duke storage ring to suppress multi-bunch beam instabilities
             which prevent stable, high-current operation of the storage
             ring based free-electron lasers (FELs) and an FEL driven
             Compton gamma source, the high intensity gamma-ray source
             (HIGS) at Duke University. In this work, we report the
             development of a state-of-the-art second generation
             longitudinal feedback system which employs a field
             programmable gate array (FPGA) based processor, and a
             broadband, high shunt-impedance kicker cavity. With two
             inputs and two outputs, the kicker cavity was designed with
             a resonant frequency of 937 MHz, a bandwidth of 97 MHz, and
             a shunt impedance of 1530Ω. We also developed an S-matrix
             based technique to fully characterize the performance of the
             kicker cavity in the cold test. This longitudinal feedback
             system has been commissioned and optimized to stabilize
             high-current electron beams with a wide range of electron
             beam energies (250 MeV to 1.15 GeV) and a number of electron
             beam bunch modes, including the single-bunch mode and all
             possible symmetric bunch modes. This feedback system has
             become a critical instrument to ensure stable, high-flux
             operation of HIGS to produce nearly monochromatic, highly
             polarized Compton gamma-ray beams. © 2010 Elsevier B.V. All
             rights reserved.},
   Doi = {10.1016/j.nima.2010.12.077},
   Key = {fds249328}
}

@article{fds191675,
   Author = {W. Xu and D. He and W. Z.Wu and Y. K. Wu},
   Title = {Design of Longitudinal Feedback Kicker for HLS Storage
             Ring},
   Journal = {Proceedings of the 2011 Particle Accelerator Conference
             (PAC'11)},
   Pages = {612 -- 614},
   Year = {2011},
   Month = {March},
   Key = {fds191675}
}

@article{fds191676,
   Author = {Y. K. Wu and J. Y. Li and S. F. Mikhailov and V. G. Popov and G. Swift and P. Wallace and W. Z. Wu and S. Huang},
   Title = {A VUV FEL for Producing 70 -- 100 MeV Circularly Polarized
             Compton Gamma-ray Beams},
   Journal = {Proceedings of the 2011 Particle Accelerator Conference
             (PAC'11)},
   Pages = {778 -- 780},
   Year = {2011},
   Month = {March},
   Key = {fds191676}
}

@article{fds191677,
   Author = {S. Huang and B. Jia and J. Y. Li and Y. K. Wu},
   Title = {Calibration of Spectrometers with Undulator
             Radiation},
   Journal = {Proceedings of the 2011 Particle Accelerator Conference
             (PAC'11)},
   Pages = {2402 -- 2404},
   Year = {2011},
   Month = {March},
   Key = {fds191677}
}

@article{fds191678,
   Author = {J. Y. Li and B. Jia and S. F. Mikhailov and V. Popov and Y. K. Wu and S.
             Huang},
   Title = {Manipulating the FEL gain process with an In-cavity Aperture
             Syste},
   Journal = {Proceedings of the 2011 Particle Accelerator Conference
             (PAC'11)},
   Pages = {2405 -- 2407},
   Year = {2011},
   Month = {March},
   Key = {fds191678}
}

@article{fds191679,
   Author = {S. F. Mikhailov and J. Y. Li and V. Popov and Y. K.
             Wu},
   Title = {Experience of FEL Mirror Degradation at the Duke FEL and
             HIGS Facility},
   Journal = {Proceedings of the 2011 Particle Accelerator Conference
             (PAC'11)},
   Pages = {2489 -- 2491},
   Year = {2011},
   Month = {March},
   Key = {fds191679}
}

@article{fds191680,
   Author = {V. Popov and J. Y. Li and S. F. Mikhailov and P. Wallace and P. Wang and Y.
             K. Wu},
   Title = {Upgrade of the RF Photo-Injector for the Duke Storage
             Ring},
   Journal = {Proceedings of the 2011 Particle Accelerator Conference
             (PAC'11)},
   Pages = {2408 -- 2410},
   Year = {2011},
   Month = {March},
   Key = {fds191680}
}

@article{fds249360,
   Author = {Sun, C and Wu, YK},
   Title = {Theoretical and simulation studies of characteristics of a
             Compton light source},
   Journal = {Physical Review Special Topics - Accelerators and
             Beams},
   Volume = {14},
   Number = {4},
   Pages = {044701},
   Year = {2011},
   ISSN = {1098-4402},
   url = {http://dx.doi.org/10.1103/PhysRevSTAB.14.044701},
   Abstract = {Compton scattering of a laser beam with a relativistic
             electron beam has been used to generate intense, highly
             polarized and nearly monoenergetic x-ray or gamma-ray beams
             at many facilities. The ability to predict the spatial,
             spectral, and temporal characteristics of a Compton
             gamma-ray beam is crucial for the optimization of the
             operation of a Compton light source as well as for the
             applications utilizing the Compton beam. In this paper, we
             present two approaches, one based upon analytical
             calculations and the other based upon Monte Carlo
             simulations, to study the Compton scattering process for
             various electron and laser-beam parameters as well as
             different gamma-beam collimation conditions. These
             approaches have been successfully applied to characterize
             Compton gamma-ray beams, after being benchmarked against
             experimental results at the High Intensity Gamma-ray Source
             (HIγS) facility at Duke University. © 2011 American
             Physical Society.},
   Doi = {10.1103/PhysRevSTAB.14.044701},
   Key = {fds249360}
}

@article{fds249361,
   Author = {Quarati, FGA and Owens, A and Dorenbos, P and Haas, JTMD and Benzoni, G and Blasi, N and Boiano, C and Brambilla, S and Camera, F and Alba, R and Bellia, G and Maiolino, C and Santonocito, D and Ahmed, M and Brown, N and Stave, S and Weller, HR and Wu, YK},
   Title = {High energy gamma-ray spectroscopy with LaBr3
             scintillation detectors},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {629},
   Number = {1},
   Pages = {157-169},
   Year = {2011},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/j.nima.2010.11.035},
   Abstract = {Lanthanum bromide scintillation detectors produce very high
             light outputs (∼60,000 ph/MeV) within a very short decay
             time (typically ∼20 ns) which means that high
             instantaneous currents can be generated in the photocathode
             and dynode chain of the photomultiplier tube (PMT) used for
             the scintillation readout. The net result is that signal
             saturation can occur long before the recommended PMT biasing
             conditions can be reached. In search of an optimized light
             readout system for LaBr3, we have tested and compared two
             different PMT configurations for detection of gamma-rays up
             to 15 MeV. This range was chosen as being appropriate for
             gamma-ray remote sensing and medium energy nuclear physics
             applications. The experiments were conducted at two
             facilities: the Laboratori Nazionali del Sud (LNS) in
             Catania, Italy [1] and the High Intensity Gamma-ray Source
             (HIγS) at Triangle University Nuclear Laboratory, in
             Durham, North Carolina, USA [2]. The PMT configurations we
             have tested are (1) a standard dynode chain operated
             under-biased; (2) a 4-stage reduced chain operated at
             nominal inter-dynode bias. The results are that shortening
             the number of active stages, as in configuration (2), has
             advantages in preserving energy resolution and avoiding PMT
             saturation over a large energy range. However, the use of an
             under-biased PMT, configuration (1), can still be considered
             a satisfactory solution, at least in the case of PMTs
             manufactured by Photonis. The results of this study will be
             used in support of the Mercury Gamma-ray and Neutron
             Spectrometer (MGNS) on board of BepiColombo, the joint
             ESA/JAXA mission to Mercury, scheduled for launch in 2014.
             © 2010 Elsevier B.V. All rights reserved.},
   Doi = {10.1016/j.nima.2010.11.035},
   Key = {fds249361}
}

@article{fds249251,
   Author = {Wu, YK},
   Title = {Accelerator physics research and light source development at
             Duke University},
   Journal = {IPAC 2010 - 1st International Particle Accelerator
             Conference},
   Pages = {2648-2650},
   Year = {2010},
   Month = {December},
   Abstract = {The accelerator physics and light source development
             programs at the Duke Free-Electron Laser Laboratory (DFELL)
             focus on beam dynamics research, beam instability studies,
             FEL research, and the development of storage ring based
             free-electron lasers (FELs) and Compton gamma-ray sources.
             The High Intensity Gamma-ray Source (HIγS) at Duke
             University is the highest flux Compton gamma-ray source
             currently available with an energy tuning range from 1 to
             100 MeV. In this paper, we will report our recent progress
             in accelerator physics research and light source development
             to meet challenges of today's and future
             accelerators.},
   Key = {fds249251}
}

@article{fds249252,
   Author = {Sun, C and Wu, YK},
   Title = {A semi-analytical algorithm for modelling Compton gamma-ray
             beams},
   Journal = {IPAC 2010 - 1st International Particle Accelerator
             Conference},
   Pages = {265-267},
   Year = {2010},
   Month = {December},
   Abstract = {Compton scattering of a laser beam with a relativistic
             electron beam has been used to generate an intense, highly
             polarized, and nearly monoenergetic gamma-ray beam at
             several facilities. The ability of predicting the spatial
             and spectral distributions of a Compton gamma-ray beam is
             crucial for the optimization of the operation of a Comp-ton
             light source as well as for the applications utilizing the
             Compton beam. In this paper, we present an analytical
             algorithm for modelling Compton scattering process. Based
             upon this algorithm, we developed a numerical integration
             code to produce smooth results for the spatial and spectral
             distributions of the Compton beam. This code has been used
             to characterize the High Intensity Gamma-ray Source (HI γ
             S) at Duke University for varying electron and laser beam
             parameters as well as different gamma-ray beam col-limation
             conditions.},
   Key = {fds249252}
}

@article{fds249253,
   Author = {Mikhailov, SF and Popov, VG and Li, J and Wu, YK},
   Title = {Study of FEL mirror degradation at the DUKE FEL and higs
             facility},
   Journal = {IPAC 2010 - 1st International Particle Accelerator
             Conference},
   Pages = {2275-2277},
   Year = {2010},
   Month = {December},
   Abstract = {The Duke FEL and High Intensity Gamma-ray Source (HIγS) are
             operated with a wide range of electron beam energies
             (0.24-1.2 GeV) and photon beam wavelengths (190-1060 nm).
             Currently, the HIγS user operation is carried out in the
             gamma-beam energy range from 1 to about 65 MeV, with a
             near-future extension to about 100 MeV using 190 nm FEL
             mirrors. The maximum total gamma-flux produced at the HIγS
             facility is up to 10 10 gammas per second around 10 MeV.
             Production of this high level gamma-ray flux requires a very
             high average FEL photon beam power inside the FEL resonator
             at one kilowatt or more. The high power FEL operation can
             cause significant degradation of the FEL mirrors due to
             higher-order wiggler harmonic radiation, especially when
             operating the FEL in the UV region at a high electron beam
             energy. This has limited the high-energy, high-flux HIγS
             gamma-beam operation mostly to circular polarization when UV
             mirrors are used, as higher-order harmonic radiation of
             helical wigglers is peaked off-axis. To ensure the
             predictability and stability of the HIγS operation for user
             research program, we have developed a comprehensive program
             to continuously monitor the performance of the FEL mirrors.
             This program has enabled us to use a particular set of FEL
             mirrors for a few hundreds hours of high gamma-flux
             operation with predictable performance. In this work, we
             discuss sources and consequences of the mirror degradation
             for a variety of wavelengths.},
   Key = {fds249253}
}

@article{fds249254,
   Author = {Sun, C and Li, J and Wu, WZ and Mikhailov, SF and Popov, VG and Wu, YK and Zhang, J and Xu, HL and Chao, AW},
   Title = {Electron beam polarization measurement using touschek
             lifetime technique},
   Journal = {IPAC 2010 - 1st International Particle Accelerator
             Conference},
   Pages = {262-264},
   Year = {2010},
   Month = {December},
   Abstract = {Electron beam loss due to intra-beam scattering, the
             Tou-schek effect, in a storage ring depends on the electron
             beam polarization. The polarization of an electron beam can
             be determined from the difference in the Touschek lifetime
             compared with an unpolarized beam. In this paper, we report
             on a systematic experimental procedure recently developed at
             Duke FEL laboratory to study the radiative polarization of a
             stored electron beam. Using this technique, we have
             successfully observed the radiative polarization build-up of
             an electron beam in the Duke storage ring, and determined
             the equilibrium degree of polarization and the time constant
             of the polarization build-up process.},
   Key = {fds249254}
}

@article{fds249371,
   Author = {Jia, B and Wu, YK and Bisognano, JJ and Chao, AW and Wu,
             J},
   Title = {Influence of an imperfect energy profile on a seeded free
             electron laser performance},
   Journal = {Physical Review Special Topics - Accelerators and
             Beams},
   Volume = {13},
   Number = {6},
   Pages = {060701},
   Year = {2010},
   ISSN = {1098-4402},
   url = {http://hdl.handle.net/10161/4309 Duke open
             access},
   Abstract = {A single-pass high-gain x-ray free electron laser (FEL)
             calls for a high quality electron bunch. In particular, for
             a seeded FEL amplifier and for a harmonic generation FEL,
             the electron bunch initial energy profile uniformity is
             crucial for generating an FEL with a narrow bandwidth. After
             the acceleration, compression, and transportation, the
             electron bunch energy profile entering the undulator can
             acquire temporal nonuniformity. We study the influence of
             the electron bunch initial energy profile nonuniformity on
             the FEL performance. Intrinsically, for a harmonic
             generation FEL, the harmonic generation FEL in the final
             radiator starts with an electron bunch having energy
             modulation acquired in the previous stages, due to the FEL
             interaction at those FEL wavelengths and their harmonics.
             The influence of this electron bunch energy nonuniformity on
             the harmonic generation FEL in the final radiator is then
             studied. © 2010 The American Physical Society.},
   Doi = {10.1103/PhysRevSTAB.13.060701},
   Key = {fds249371}
}

@article{fds249372,
   Author = {Sun, C and Zhang, J and Li, J and Wu, WZ and Mikhailov, SF and Popov, VG and Xu, HL and Chao, AW and Wu, YK},
   Title = {Polarization measurement of stored electron beam using
             Touschek lifetime},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {614},
   Number = {3},
   Pages = {339-344},
   Year = {2010},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/j.nima.2010.01.034},
   Abstract = {Touschek lifetime of an electron beam in a storage ring
             depends on the beam polarization through the intrabeam
             scattering effect. Therefore, the electron beam polarization
             can be determined from the Touschek lifetime measurement. In
             this paper, we report on a systematic experimental procedure
             we developed to study the radiative polarization of a stored
             electron beam. Using this technique, we successfully
             observed the radiative polarization of an electron beam in
             the Duke storage ring, and determined the equilibrium degree
             of polarization and the time constant of the polarization
             build-up process. © 2010 Elsevier B.V.},
   Doi = {10.1016/j.nima.2010.01.034},
   Key = {fds249372}
}

@article{fds249373,
   Author = {Jia, B and Li, J and Huang, S and Schmidler, SC and Wu,
             YK},
   Title = {Electron beam energy spread measurements using optical
             klystron radiation},
   Journal = {Physical Review Special Topics - Accelerators and
             Beams},
   Volume = {13},
   Number = {8},
   Pages = {080702},
   Year = {2010},
   ISSN = {1098-4402},
   url = {http://hdl.handle.net/10161/4310 Duke open
             access},
   Abstract = {In accelerators, the electron beam longitudinal dynamics
             critically depend on the energy distribution of the beam.
             Noninvasive, highly accurate measurement of the energy
             spread of the electron beam in the storage ring remains a
             challenge. Conventional techniques are limited to measuring
             a relatively large energy spread using the energy spread
             induced broadening effect of radiation source size or
             radiation spectrum. In this work, we report a versatile
             method to accurately measure the electron beam relative
             energy spread from 10 -4 to 10-2 using the optical klystron
             radiation. A novel numerical method based on the
             Gauss-Hermite expansion has been developed to treat both
             spectral broadening and modulation on an equal footing. A
             large dynamic range of the measurement is realized by
             properly configuring the optical klystron. In addition, a
             model-based scheme has been developed for the first time to
             compensate the beam-emittance-induced inhomogeneous spectral
             broadening effect to improve the accuracy of the energy
             spread measurement. Using this technique, we have
             successfully measured the relative energy spread of the
             electron beam in the Duke storage ring from 6×10-4 to
             6×10-3 with an overall uncertainty of less than 5%. The
             optical klystron is a powerful diagnostic for highly
             accurate energy spread measurement for storage rings and
             other advanced electron accelerators. © 2010 The American
             Physical Society.},
   Doi = {10.1103/PhysRevSTAB.13.080702},
   Key = {fds249373}
}

@article{fds249379,
   Author = {Rusev, G and Tonchev, AP and Schwengner, R and Sun, C and Tornow, W and Wu,
             YK},
   Title = {Multipole mixing ratios of transitions in
             B-11},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {79},
   Number = {4},
   Pages = {047601},
   Year = {2009},
   Month = {April},
   ISSN = {0556-2813},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000266634300076&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {Photon scattering experiments with photon energies up to 3.6
             MeV have been performed on the axially deformed nucleus
             164Dy. We observe the -decay from the scissors mode to the
             -vibration for the first time in a well-deformed rotor.
             Previous ambiguities in the level scheme are resolved by a
             novel spectroscopic usage of the nearly-monochromatic photon
             beam from laser-Compton backscattering. The observed decay
             rate is sensitive to the finite size of the nuclear quantum
             system.},
   Doi = {10.1103/PhysRevC.79.047601},
   Key = {fds249379}
}

@article{fds191672,
   Author = {S. Huang and J. Y. Li and Y. K. Wu},
   Title = {Experiments on Madey Theorem with Optical Klystron
             Free-Electron Laser},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1244-1246},
   Year = {2009},
   Abstract = {The Madey the­o­rem is a valu­able re­search tool for
             study­ing Free-Elec­tron Lasers (FELs). The the­o­rem
             re­lates the shape of the on-ax­is spon­ta­neous
             ra­di­a­tion spec­trum of FEL wig­glers to the FEL
             gain. The the­o­rem pre­dicts that degra­da­tion of the
             spon­ta­neous spec­trum, for ex­am­ple as a re­sult of
             the in­crease of the elec­tron beam en­er­gy spread,
             pro­vides a di­rect mea­sure of the re­duc­tion of the
             FEL gain. Ex­ten­sive ex­per­i­ments have been
             per­formed to study the va­lid­i­ty of the Madey
             the­o­rem for a stor­age ring base op­ti­cal klystron
             FEL. The ex­per­i­men­tal data show that the las­ing
             wave­length of the FEL is very close to the max­i­mum
             slope of spon­ta­neous spec­tra as pre­dict­ed by the
             Madey the­o­rem with a rel­a­tive wave­length
             dis­crep­an­cy less than 0.2%. Fur­ther anal­y­sis is
             un­der­way to un­der­stand this wave­length
             dif­fer­ence. In ad­di­tion, we have per­formed
             di­rect mea­sure­ments of the start up gain of the FEL
             and com­pared it with the chang­ing slope of the
             spon­ta­neous spec­tra. The pre­lim­i­nary re­sults
             show a good agree­ment be­tween the mea­sured FEL gain
             and the pre­dic­tion by Madey the­o­rem.},
   Key = {fds191672}
}

@article{fds191673,
   Author = {Y. K. Wu},
   Title = {Accelerator Physics Research and Development Programs at
             Duke University},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1245-1247},
   Year = {2009},
   Abstract = {The Duke Free-Elec­tron Laser Lab­o­ra­to­ry (DFELL)
             op­er­ates sev­er­al ac­cel­er­a­tors as a driv­er
             for stor­age ring based Free-Elec­tron Lasers (FELs) and
             Comp­ton gam­ma-ray source, the High In­ten­si­ty
             Gam­ma-ray Source (HIGS). The HIGS is the most pow­er­ful
             Comp­ton gam­ma-ray source in the world below 100 MeV.
             Since com­plet­ing a major up­grade of the HIGS in 2007,
             the Duke stor­age ring FEL and HIGS gamma source have been
             op­er­at­ed ex­ten­sive­ly for user re­search
             pro­grams. In 2008, the DFELL was merged with the
             Tri­an­gle Uni­ver­si­ties Nu­cle­ar
             Lab­o­ra­to­ry (TUNL) to be­come a major
             ac­cel­er­a­tor fa­cil­i­ty of the TUNL. The
             ac­cel­er­a­tor physics pro­gram at the DFELL cov­ers
             a wide range of ac­tiv­i­ties, from non­lin­ear
             dy­nam­ics re­search, to the study of beam
             in­sta­bil­i­ty with ad­vanced feed­back sys­tems, to
             light source re­search and de­vel­op­ment, in
             par­tic­u­lar, the FEL re­search and Comp­ton light
             source de­vel­op­ment. In this paper, we will re­port
             our re­cent progress in ac­cel­er­a­tor physics
             re­search and light source de­vel­op­ment to meet new
             chal­lenges of today's and fu­ture ac­cel­er­a­tors.},
   Key = {fds191673}
}

@article{fds167635,
   Author = {Y. K. Wu},
   Title = {Storage Ring Compton Gamma-ray Source},
   Journal = {ICFA Beam Dynamics Newsletter},
   Volume = {50},
   Editor = {W. Chou},
   Year = {2009},
   Key = {fds167635}
}

@article{fds167637,
   Author = {Y. K. Wu and M. Busch and M. Emamian and J. Faircloth and S. Hartman and C.
             Howell, J. Li and S. Mikhailov and V. Popov and G. Swift and P. Wallace and P. Wang},
   Title = {Performance and Capabilities of Upgraded High Intensity
             Gamma-ray Source at Duke University},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {3181-3183},
   Year = {2009},
   Abstract = {Since 2008, the up­grad­ed High In­ten­si­ty
             Gam­ma-ray Source (HIGS) at the Duke FEL Lab has
             pro­vid­ed users with gamma beams of un­prece­dent­ed
             qual­i­ty for sci­en­tif­ic re­search. The
             re­cent­ly com­plet­ed ac­cel­er­a­tor up­grades
             in­clude a HOM-damped RF cav­i­ty, a full-en­er­gy
             top-off boost­er in­jec­tor, re­designed stor­age ring
             straight sec­tions, and two new FELs. The HIGS
             fa­cil­i­ty is now ca­pa­ble of pro­duc­ing a high
             in­ten­si­ty gamma beam in a wide en­er­gy range (1 -
             100 MeV) using com­mer­cial FEL mir­rors. It has achieved
             an ex­cep­tion­al­ly high flux, up to ~1010 g/s total (<
             20 MeV), mak­ing it the world's most pow­er­ful Comp­ton
             gamma source. It pro­duces al­most 100% po­lar­ized
             gam­mas, ei­ther lin­ear or cir­cu­lar. At the HIGS,
             the gamma en­er­gy can be changed rapid­ly with­in a
             fac­tor of three in min­utes. Op­er­at­ed by
             Tri­an­gle Uni­ver­si­ties Nu­cle­ar
             Lab­o­ra­to­ry since sum­mer 2008, the HIGS is a
             ded­i­cat­ed Comp­ton gamma source, ca­pa­ble of
             pro­duc­ing more than 2,000 h of gamma beam time per year
             with a five-day, two-shift sched­ule. Fu­ture
             de­vel­op­ment at the HIGS in­cludes high­er en­er­gy
             gamma beams to­ward the pion thresh­old and a rapid switch
             of cir­cu­lar po­lar­iza­tion.},
   Key = {fds167637}
}

@article{fds167638,
   Author = {Stepan. F. Mikhailov and Jngyi Li and Victor Popov and Patrick W.
             Wallace and Ping Wang and Ying K. Wu and Oleg Anchugov},
   Title = {Multibunch injection scheme for the Duke booster synchrotron
             for top-off injection},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1238-1240},
   Year = {2009},
   Abstract = {A boost­er-in­jec­tor syn­chrotron has been re­cent­ly
             built and com­mis­sioned at Duke Uni­ver­si­ty to
             pro­vide for the top-off in­jec­tion into the stor­age
             ring in the en­er­gy range of 0.24 - 1.2 GeV. Boost­er
             in­jec­tion kick­er was de­signed with a pulse length of
             18 out of 19 boost­er sep­a­ra­trix­es, as­sum­ing a
             long train of elec­tron bunch­es to be in­ject­ed from
             the ex­ist­ing linac. Such scheme re­quired a major linac
             up­grade from sin­gle bunch photo emis­sion mode to a
             multi­bunch thermion­ic mode. A major dis­ad­van­tage
             of the lat­ter was much high­er ra­di­a­tion lev­els
             in the fa­cil­i­ty. Since com­mis­sion­ing, the
             boost­er could only op­er­ate with one or two bunch­es
             lim­it­ed by both long kick­er pulse and sin­gle bunch
             in­jec­tion from the linac. The con­se­quent
             lim­i­ta­tion of the in­jec­tion rate re­strict­ed
             the ca­pa­bil­i­ty of pro­duc­tion of the Comp­ton
             gamma rays in the loss mode, i.e. pro­duc­tion of gam­mas
             with en­er­gy above 20-25 MeV, to about 5*108 pho­tons
             per sec. Up­date of the linac for the rep­e­ti­tion rate
             of up to 10 Hz, and mod­i­fi­ca­tion of the
             in­jec­tion kick­er for 15 nS pulse length al­lowed us
             to de­vel­oped an al­ter­na­tive multi­bunch
             in­jec­tion scheme with a sig­nif­i­cant in­crease of
             the in­jec­tion rate into stor­age ring.},
   Key = {fds167638}
}

@article{fds167639,
   Author = {Stepan F. Mikhailov and Jingyi Li and Victor Popov and Ying K.
             Wu},
   Title = {Pass-by-pass multistage FEL gain measurement technique for a
             storage ring FEL},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1241-1243},
   Year = {2009},
   Abstract = {The paper pre­sents a novel tech­nique of mea­sur­ing
             the gain of a stor­age ring based FEL os­cil­la­tor. As
             op­posed to the con­ven­tion­al tech­nique of
             mea­sur­ing the FEL gain from its macro-pulse
             en­ve­lope, this new tech­nique is based upon the
             mea­sure­ment of pass-by-pass FELμpuls­es. To record the
             growth of the op­ti­cal en­er­gy in the FEL
             mi­cro-pulse train, we use fast pho­to-diodes and
             pho­to-mul­ti­pli­er tubes (PMTs). PMTs are usu­al­ly
             em­ployed at the very be­gin­ning of the FEL las­ing
             de­vel­op­ment, while the pho­to­di­odes are used at
             the lat­ter stages when the FEL power is fully
             de­vel­oped and sat­u­rat­ed. This new gain
             mea­sure­ment tech­nique pro­vides a pow­er­ful tool
             to study the de­tails of the FEL gain pro­cess start­ing
             from spon­ta­neous ra­di­a­tion to sat­u­ra­tion. It
             al­lows us to in­ves­ti­gate five to seven or­ders of
             mag­ni­tude of the FEL en­er­gy growth. As fast
             pho­to-de­tec­tors with a sub-nanosec­ond time
             re­sponse be­come avail­able, this new tech­nique can be
             adopt­ed for many os­cil­la­tor FELs, in­clud­ing
             those driv­en by su­per-con­duct­ing linacs. Spe­cial
             at­ten­tion is paid to the dy­nam­ic non-lin­ear­i­ty
             is­sues of the pho­to­di­odes and PMTs
             as­so­ci­at­ed with short length of FEL
             puls­es.},
   Key = {fds167639}
}

@article{fds167640,
   Author = {H. Hao and X. Q. Wang and Y. K. Wu},
   Title = {Nonlinear Dynamics Study of Storage Ring with Super
             Periods},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1904-1906},
   Year = {2009},
   Abstract = {Many mod­ern light source stor­age rings use a basic
             mag­net­ic lat­tice struc­ture con­sist­ing of a
             num­ber of repet­i­tive pe­ri­od­ic lat­tice block,
             the super pe­ri­ods. The study of one su­per-pe­ri­od
             can re­veal the dy­nam­i­cal pro­pri­eties of the
             stor­age ring. Un­like the tra­di­tion­al ap­proach of
             study­ing the one-turn map of the stor­age ring, the work
             fo­cus­es on the study of a su­per-pe­ri­od lat­tice,
             which al­lows us to gain new in­sight into the stor­age
             ring dy­nam­ics using a sim­pler mag­net­ic
             struc­ture. In this paper, both an­a­lyt­i­cal and
             nu­mer­i­cal tech­niques, in­clud­ing Lie Al­ge­bra
             and Nor­mal Form, and par­ti­cle track­ing and
             fre­quen­cy anal­y­sis, are used to study the
             non­lin­ear dy­nam­ics of one su­per-pe­ri­od of a
             stan­dard dou­ble-bend achro­mat (DBA) and triple-bend
             achro­mat (TBA) with two or more non­lin­ear el­e­ments
             (e.g. sex­tupoles). The re­la­tion­ship be­tween the
             su­per-pe­ri­od dy­nam­ics and stor­age ring
             dy­nam­ics is ex­plored in terms of the glob­al
             lat­tice tun­ing and local lat­tice se­lec­tion for
             straight sec­tions.},
   Key = {fds167640}
}

@article{fds167641,
   Author = {W. Z. Wu and Y. Kim and J. Li and Ping Wang and Matthew Busch and Gary
             Swift, Ying K. Wu and Dmitry Teytelman and In-Soo Park and In Soo
             Ko},
   Title = {Development and commissioning of bunch-by-bunch longitudinal
             feedback system for Duke storage ring},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {4117-4119},
   Year = {2009},
   Abstract = {The cou­pled bunch mode in­sta­bil­i­ties (CBMIs)
             caused by vac­u­um cham­ber impedance limit and de­grade
             the per­for­mance of the stor­age ring based light
             sources. A bunch-by-bunch lon­gi­tu­di­nal feed­back
             (LFB) sys­tem has been de­vel­oped to sta­bi­lize beams
             for the op­er­a­tion of a stor­age ring based Free
             Elec­tron Laser (FEL) and the High In­ten­si­ty
             Gam­ma-ray Source (HIGS) at the Duke stor­age ring.
             Em­ploy­ing a Gi­ga-sam­ple FPGA based pro­ces­sor
             (iGP), the LFB is ca­pa­ble of damp­ing out the dipole
             mode os­cil­la­tion for all 64 bunch­es. As a
             crit­i­cal sub­sys­tem of the LFB sys­tem, kick­er
             cav­i­ty is de­vel­oped with a cen­ter fre­quen­cy of
             938 MHz, a wide band­width (> 90 MHz), and a high shunt
             impedance (> {10}00 Ω). First com­mis­sioned in sum­mer
             2008, the LFB has been op­er­at­ed to sta­bi­lize high
             cur­rent mul­ti-bunch op­er­a­tion. More re­cent­ly,
             the LFB sys­tem is demon­strat­ed as a crit­i­cal
             in­stru­ment to en­sure sta­ble op­er­a­tion of the
             HIGS with a high in­ten­si­ty gamma beam above 20 MeV
             with a fre­quent top-off in­jec­tion to com­pen­sate
             for the sub­stan­tial and con­tin­u­ous elec­tron beam
             loss in the Comp­ton scat­ter­ing pro­cess. In the
             fu­ture, we will per­form de­tailed stud­ies of the
             impedance ef­fects using the LFB sys­tem.},
   Key = {fds167641}
}

@article{fds167642,
   Author = {C. Sun and Y. K. Wu and J. Li and G. Rusev and A. P.
             Tonchev},
   Title = {Accurate energy measurement of an electron beam in a storage
             ring using Compton scattering technique},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {3552-3554},
   Year = {2009},
   Abstract = {A gam­ma-ray beam pro­duced by Comp­ton scat­ter­ing of
             a laser beam and a rel­a­tivis­tic elec­tron beam has
             been used to de­ter­mine elec­tron beam pa­ram­e­ters.
             In order to ac­cu­rate­ly mea­sure the elec­tron beam
             en­er­gy, a fit­ting model based upon Comp­ton
             scat­ter­ing cross sec­tion is in­tro­duced in this
             paper. With this model, we have suc­cess­ful­ly
             de­ter­mined the en­er­gy of the elec­tron beam in Duke
             stor­age ring with a rel­a­tive un­cer­tain­ty of 3×
             10-5 using a Comp­ton gamma beam from the High
             In­ten­si­ty γ-ray Source (HIγS) fa­cil­i­ty at Duke
             Uni­ver­si­ty.},
   Key = {fds167642}
}

@article{fds167643,
   Author = {C. Sun and Y. K. Wu and G. Rusev and A. P. Tonchev},
   Title = {End-to-End Spectrum Reconstruction of Compton Gamma-Ray Beam
             to Determine Electron Beam Parameter},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1363-1365},
   Year = {2009},
   Abstract = {A gam­ma-ray beam pro­duced by Comp­ton scat­ter­ing of
             a laser beam with a rel­a­tivis­tic elec­tron beam has
             been used to de­ter­mine the elec­tron beam
             pa­ram­e­ters. In the past, the elec­tron beam
             en­er­gy and en­er­gy spread were di­rect­ly fit from
             the high en­er­gy edge of a mea­sured gamma beam
             spec­trum using a gam­ma-ray de­tec­tor. How­ev­er,
             due to non-ide­al re­sponse of the de­tec­tor, the
             mea­sured spec­trum can­not rep­re­sent the true
             en­er­gy dis­tri­bu­tion of the gam­ma-ray beam. Thus,
             the elec­tron beam en­er­gy and en­er­gy spread could
             not be ac­cu­rate­ly de­ter­mined from the mea­sured
             gamma beam spec­trum. In this paper, we will pre­sent a
             novel end-to-end spec­trum re­con­struc­tion method to
             ac­cu­rate­ly ex­tract the en­er­gy dis­tri­bu­tion
             of the gam­ma-ray beam from the mea­sured gamma beam
             spec­trum. Using this method we have ac­cu­rate­ly
             de­ter­mined the en­er­gy and en­er­gy spread of the
             elec­tron beam in Duke stor­age ring using a Comp­ton
             gam­ma-ray beam from the High In­ten­si­ty γ-ray Source
             (HIγS) fa­cil­i­ty.},
   Key = {fds167643}
}

@article{fds167646,
   Author = {J. Li and S. Huang and Y. K. Wu},
   Title = {FEL transverse mode manipulation using an in-cavity aperture
             system},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1235-1237},
   Year = {2009},
   Abstract = {The stor­age ring based free elec­tron laser (FEL)
             os­cil­la­tor serves as a pho­ton driv­er for the High
             In­ten­si­ty Gam­ma-Ray Source (HIGS) at Duke
             Uni­ver­si­ty. The FEL cav­i­ty con­sists of two
             con­cave mir­rors with a large ra­dius of cur­va­ture
             of more than 27 m. Both cav­i­ty mir­rors see very high
             in­ten­si­ty in­tra­cav­i­ty FEL power; the
             down­stream mir­ror also re­ceives high­er har­mon­ic
             spon­ta­neous UV-VUV ra­di­a­tion of wig­glers. The
             large heat load by var­i­ous types of ra­di­a­tion can
             de­form the mir­ror sur­face, caus­ing FEL mode
             dis­tor­tion. The FEL mir­ror can also be dam­aged by
             in­tense UV-VUV wig­gler har­mon­ic ra­di­a­tion. To
             mit­i­gate these prob­lems, a pair of wa­ter-cooled,
             in-vac­u­um aper­tures have been in­stalled in­side the
             FEL cav­i­ty. These aper­tures are ideal for
             ma­nip­u­lat­ing the FEL trans­verse pro­file. This
             paper re­ports our study on the FEL trans­verse mode
             shap­ing using these aper­tures, in­clud­ing the
             char­ac­ter­i­za­tion of the trans­verse mode
             struc­ture of the FEL beam under a va­ri­ety of
             op­er­a­tion con­di­tions. These stud­ies allow us to
             min­i­mize the diffrac­tion loss of the fun­da­men­tal
             mode of the FEL while ef­fec­tive­ly re­duc­ing the
             im­pact of off-ax­is UV-VUV wig­gler ra­di­a­tion on
             the FEL mir­rors.},
   Key = {fds167646}
}

@article{fds167644,
   Author = {J. Zhang and C. Sun and W. Wu and J. Li and Y. K. Wu and A. W.
             Chao},
   Title = {Feasibility study of electron beam polarization measurement
             using Touschek lifetime},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1671-1673},
   Year = {2009},
   Abstract = {Tou­schek scat­ter­ing is the dom­i­nant loss
             mech­a­nism for the elec­tron beam in a low en­er­gy
             stor­age ring with a large bunch cur­rent. The Duke
             Free-Elec­tron Laser (FEL) stor­age ring typ­i­cal­ly
             op­er­ates in the one-bunch or two-bunch mode with a very
             high bunch cur­rent and a vary­ing elec­tron beam
             en­er­gy as low as 250 MeV. The study of the Tou­schek
             life­time is im­por­tant for im­prov­ing the
             per­for­mance of the Duke stor­age ring based light
             sources, in­clud­ing the stor­age ring FELs and a FEL
             driv­en Comp­ton gamma source, the High In­ten­si­ty
             Gam­ma-ray Source. This work re­ports our life­time
             mea­sure­ment re­sults for few-bunch op­er­a­tion of
             the Duke stor­age ring. The Tou­schek loss rate is
             re­duced when an elec­tron beam is po­lar­ized in the
             stor­age ring. The change of the Tou­schek life­time can
             be used as a method to mon­i­tor po­lar­iza­tion of the
             elec­tron beam. In this work, we will also re­port our
             pre­lim­i­nary re­sults of the elec­tron beam
             en­er­gy mea­sure­ments using the res­o­nant
             de­po­lar­iza­tion tech­nique.},
   Key = {fds167644}
}

@article{fds167645,
   Author = {B. Jia and J. Li and Y. K. Wu},
   Title = {Experimental study of storage ring FEL output power scaling
             with electron beam energy spread},
   Journal = {Proceedings of 2009 Particle Accelerator
             Conference},
   Pages = {1248-1250},
   Year = {2009},
   Abstract = {Ac­cu­rate si­mul­ta­ne­ous mea­sure­ments of
             stor­age ring free-elec­tron laser (SRFEL) av­er­age
             power out­put and elec­tron beam en­er­gy spread has
             been achieved at the Duke FEL Lab­o­ra­to­ry. It is well
             known that the SRFEL power is lim­it­ed by the elec­tron
             beam syn­chrotron ra­di­a­tion power and the in­duced
             en­er­gy spread of the elec­tron beam. The two-wig­gler
             spec­trum of an op­ti­cal klystron can be used to
             de­ter­mine the en­er­gy spread of the elec­tron beam.
             Mea­sur­ing the in­ter­fer­ence pat­tern of the
             mod­u­lat­ed spon­ta­neous spec­trum with the FEL
             turned on, we are able to study the FEL power out­put as a
             func­tion of elec­tron beam en­er­gy spread. As the
             en­er­gy spread in­creas­es, the mod­u­la­tion in the
             two-wig­gler spec­trum re­duces, re­sult­ing in a
             small­er FEL gain. Dur­ing this pro­cess, the
             op­er­a­tion of an op­ti­cal klystron de­grades back
             to that of a con­ven­tion­al FEL. This paper re­ports
             our re­cent ex­per­i­ment study of tran­si­tion of the
             FEL op­er­a­tion from an op­ti­cal klystron to a
             con­ven­tion­al FEL.},
   Key = {fds167645}
}

@article{fds249327,
   Author = {Sun, C and Wu, YK},
   Title = {A 4D Monte Carlo Compton scattering code},
   Journal = {IEEE Nuclear Science Symposium Conference
             Record},
   Pages = {477-480},
   Year = {2009},
   ISSN = {1095-7863},
   url = {http://dx.doi.org/10.1109/NSSMIC.2009.5401609},
   Abstract = {Compton scattering of a laser beam and an electron beam in
             an accelerator has been used to generate an x-ray or
             gamma-ray beam at many facilities. To study the spatial,
             spectral and temporal characteristics of the Compton
             gamma-ray beam, we developed a 4-dimensional (3D space plus
             time) Monte Carlo computer simulation code (MCCMPT) to model
             the Compton scattering process. This code has been
             benchmarked against the measurement results at the High
             Intensity Gamma-ray Source (HIγS) facility at Duke
             University. ©2009 IEEE.},
   Doi = {10.1109/NSSMIC.2009.5401609},
   Key = {fds249327}
}

@article{fds249374,
   Author = {Pietralla, N and Li, TC and Fritzsche, M and Ahmed, MW and Ahn, T and Costin, A and Enders, J and Li, J and Müller, S and Neumann-Cosel, PV and Pinayev, IV and Ponomarev, VY and Savran, D and Tonchev, AP and Tornow,
             W and Weller, HR and Werner, V and Wu, YK and Zilges,
             A},
   Title = {Competition between excited core states and 1 ℏ ω
             single-particle excitations at comparable energies in
             207Pb from photon scattering},
   Journal = {Physics Letters B},
   Volume = {681},
   Number = {2},
   Pages = {134-138},
   Year = {2009},
   ISSN = {0370-2693},
   url = {http://dx.doi.org/10.1016/j.physletb.2009.09.059},
   Abstract = {The Pb (over(γ, →), γ′) photon scattering reaction has
             been studied with the nearly monochromatic, linearly
             polarized photon beams at the High Intensity γ-ray Source
             (HIγS) at the DFELL. Azimuthal scattering intensity
             asymmetries measured with respect to the polarization plane
             of the beam have been used for the first time to assign both
             the spin and parity quantum numbers of dipole excited states
             of 206,207,208Pb at excitation energies in the vicinity of
             5.5 MeV. Evidence for dominant particle-core coupling is
             deduced from these results along with information on
             excitation energies and electromagnetic transition matrix
             elements. Implications of the existence of weakly coupled
             states built on highly excited core states in competition
             with 1 ℏ ω single particle (hole) excitations at
             comparable energies are discussed. © 2009 Elsevier B.V. All
             rights reserved.},
   Doi = {10.1016/j.physletb.2009.09.059},
   Key = {fds249374}
}

@article{fds249375,
   Author = {Bernstein, AM and Ahmed, MW and Stave, S and Wu, YK and Weller,
             HR},
   Title = {Chiral dynamics in photopion physics: Theory, experiment,
             and future studies at the HIγS facility},
   Journal = {Annual Review of Nuclear and Particle Science},
   Volume = {59},
   Pages = {115-144},
   Year = {2009},
   ISSN = {0163-8998},
   url = {http://dx.doi.org/10.1146/annurev.nucl.010909.083220},
   Abstract = {We review photopion experiments on the nucleon in the
             near-threshold region. We compare the results with the
             predictions of the low-energy theorems of quantum
             chromodynamics calculated using chiral perturbation theory
             (ChPT), which is based on the spontaneous breaking of chiral
             symmetry as well as explicit breaking due to the finite
             quark masses. As a result of the vanishing of the threshold
             amplitudes in the chiral limit, the experiments are
             difficult to perform because the cross sections are small.
             Nevertheless, the field is now mature in terms of accuracy
             and sensitivity. We also discuss the accomplishments and
             limitations of past measurements, as well as future planned
             experiments at Mainz and HIγS. The technical developments
             required for the HIγS facility are emphasized. Finally, we
             show that future experiments will provide even more accurate
             tests of ChPT and will be sensitive to isospin-breaking
             dynamics due to the mass difference between the up and down
             quarks. Copyright © 2009 by Annual Reviews. All rights
             reserved.},
   Doi = {10.1146/annurev.nucl.010909.083220},
   Key = {fds249375}
}

@article{fds249376,
   Author = {Huang, S and Li, J and Wu, YK},
   Title = {Water-cooled, in-cavity apertures for high power operation
             of FEL oscillators},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {606},
   Number = {3},
   Pages = {762-769},
   Year = {2009},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/j.nima.2009.04.017},
   Abstract = {In an oscillator FEL, higher-order harmonic radiation from
             wigglers can cause serious damage to the downstream FEL
             resonator mirror and limit the maximum electron beam current
             for FEL operation due to thermal overload. These problems
             can be effectively dealt with for FELs driven by helical
             wigglers using a system to block off-axis wiggler harmonic
             radiation. In this paper, we report a new scheme to block
             the off-axis radiation from helical wigglers using a set of
             motorized, water-cooled, in-cavity apertures. These
             apertures can reduce the wiggler harmonic radiation power
             load on the downstream FEL resonator mirror by two orders of
             magnitude or more. With these apertures, we were able to
             operate the Duke FEL with record high intracavity power in
             infrared and visible wavelengths and extend FEL operation
             into ultraviolet wavelengths with a large electron beam
             current. The technique for limiting wiggler harmonic
             radiation using in-cavity apertures is expected to be useful
             for other types of FEL oscillators including high average
             power FEL oscillators driven by superconducting linacs. ©
             2009 Elsevier B.V. All rights reserved.},
   Doi = {10.1016/j.nima.2009.04.017},
   Key = {fds249376}
}

@article{fds249377,
   Author = {Sun, C and Li, J and Rusev, G and Tonchev, AP and Wu,
             YK},
   Title = {Energy and energy spread measurements of an electron beam by
             Compton scattering method},
   Journal = {Physical Review Special Topics - Accelerators and
             Beams},
   Volume = {12},
   Number = {6},
   Pages = {062801},
   Year = {2009},
   ISSN = {1098-4402},
   url = {http://dx.doi.org/10.1103/PhysRevSTAB.12.062801},
   Abstract = {A gamma-ray beam produced by Compton scattering of a laser
             beam with an electron beam can be used to measure the
             electron beam parameters. In several published works, a
             simple fitting model has been applied to determine the
             electron beam energy and energy spread without considering
             the gamma beam collimation and electron beam emittance
             effects. This fitting model is rederived in this work, and
             the underlying assumptions and resultant limitations are
             discussed. To overcome these limitations, a new fitting
             model is proposed, which takes into account the collimation
             and emittance effects. Using the new model and a gamma-ray
             beam produced at the high intensity γ-ray sources facility
             at Duke University, we have successfully determined the
             electron beam energy with a relative uncertainty of about
             3×10-5 around 460 MeV as well as the electron beam energy
             spread. We also experimentally demonstrated for the first
             time that a small relative energy change (about 4×10-5) of
             the electron beam by varying the storage ring dipole field
             can be directly detected using the Compton scattering
             technique. © 2009 The American Physical
             Society.},
   Doi = {10.1103/PhysRevSTAB.12.062801},
   Key = {fds249377}
}

@article{fds249378,
   Author = {Sun, C and Wu, YK and Rusev, G and Tonchev, AP},
   Title = {End-to-end spectrum reconstruction method for analyzing
             Compton gamma-ray beams},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {605},
   Number = {3},
   Pages = {312-317},
   Year = {2009},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/j.nima.2009.03.237},
   Abstract = {A gamma-ray beam produced by Compton scattering of a laser
             beam with a relativistic electron beam has been used for
             nuclear physics research at the high intensity γ-ray source
             (HI γ S) facility at Duke University. The success of many
             experiments using the gamma-ray beam critically depends on
             the accurate knowledge of the gamma-ray beam energy
             distribution which is typically obtained by unfolding a
             measured energy spectrum. Conventionally, the detector
             response function used in the spectrum unfolding is
             simulated by a simple Monte Carlo code in which an isotropic
             gamma-ray event generator is used. However, for a Compton
             scattered gamma-ray beam, this simulation method could lead
             to an inaccurate detector response function, since it
             neglects the spatial and energy distributions of the
             gamma-ray beam. In this paper, we will present a novel
             end-to-end gamma-ray spectrum reconstruction method by
             completely modeling the process of the Compton gamma-ray
             beam production, collimation, transportation and detection.
             Using this method, we have successfully reconstructed the
             energy distribution of HI γ S beams for nuclear physics
             research with a high degree of accuracy. © 2009 Elsevier
             B.V. All rights reserved.},
   Doi = {10.1016/j.nima.2009.03.237},
   Key = {fds249378}
}

@article{fds249380,
   Author = {Weller, HR and Ahmed, MW and Gao, H and Tornow, W and Wu, YK and Gai, M and Miskimen, R},
   Title = {Research opportunities at the upgraded HIγS
             facility},
   Journal = {Progress in Particle and Nuclear Physics},
   Volume = {62},
   Number = {1},
   Pages = {257-303},
   Year = {2009},
   ISSN = {0146-6410},
   url = {http://dx.doi.org/10.1016/j.ppnp.2008.07.001},
   Abstract = {The High Intensity γ-ray Source (HIγS) is a joint project
             between the Triangle Universities Nuclear Laboratory (TUNL)
             and the Duke Free Electron Laser Laboratory (DFELL). This
             facility utilizes intra-cavity back-scattering of the FEL
             light in order to produce intense γ-ray beams. An upgrade
             which allows for the production of γ-rays up to energies of
             about 100 MeV having total intensities in excess of 108/s is
             essentially complete. The primary component of the upgrade
             is a 1.2 GeV booster-injector which makes it possible to
             replace lost electrons at full energy. In addition, an
             upgrade of the present linear undulator to a helical system
             has made it possible to produce nearly 100% linear and
             circularly polarized beams. The full system was commissioned
             in the early part of 2007. A nuclear physics research
             program using beams at energies below 50 MeV commenced in
             the fall of 2007. The proposed experimental program includes
             low-energy studies of nuclear reactions of importance in
             nuclear astrophysics as well as studies of nuclear structure
             using the technique of nuclear resonance fluorescence (NRF).
             Few-body nuclear physics problems will also be addressed by
             studying photodisintegration of d, 3He and 4He. Future
             double-polarization experiments include a study of the
             Gerasimov-Drell-Hearn Sum Rule for the deuteron and 3He, and
             an extensive Compton scattering program designed to probe
             the internal structure of the nucleon. A major focus of
             these studies will be the measurement of the electric and
             magnetic polarizabilities as well as the
             spin-polarizabilities of the proton and the neutron. This
             review will describe the principles of operation of the
             upgraded facility, followed by a description of the
             performance which has been achieved to date, and a
             projection of the performance anticipated in the near
             future. Following this, we will review several of the
             research areas of nuclear physics which are accessible using
             this facility, and describe both the results to date and
             proposed experiments being developed for the future. © 2008
             Elsevier B.V. All rights reserved.},
   Doi = {10.1016/j.ppnp.2008.07.001},
   Key = {fds249380}
}

@article{fds249260,
   Author = {Huang, S and Swift, G and Wu, YK},
   Title = {Controlling wiggler harmonic radiation to reduce damage to
             FEL cavity mirrors},
   Journal = {30th International Free Electron Laser Conference, FEL
             2008},
   Pages = {135-138},
   Year = {2008},
   Abstract = {In an oscillator FEL, higher-order harmonic radiation from
             wigglers can cause serious damage to the downstream FEL
             resonator mirror or limit the maximum electron beam current
             for FEL operation due to thermal overload. With a helical
             wiggler, higher-order harmonic radiation is peaked off-axis.
             By blocking the off-axis wiggler harmonic power, the
             radiation damage to the FEL resonator mirror can be reduced.
             In this paper, we report a recently developed scheme to
             control the off-axis harmonic radiation from helical FEL
             wigglers using a set of motorized, water-cooled, in-vacuum
             apertures. These apertures can reduce the harmonic power
             load on the downstream FEL resonator mirror by one order of
             magnitude. With these apertures, high power FEL operation
             with a high electron beam current will become feasible in
             the UV-VUV wavelength range with Duke storage ring
             FELs.},
   Key = {fds249260}
}

@article{fds249261,
   Author = {Mikhailov, SF and Popov, VG and Huang, S and Li, J and Wu,
             YK},
   Title = {A pass-by-pass gain measurement technique for oscillator
             FELs},
   Journal = {30th International Free Electron Laser Conference, FEL
             2008},
   Pages = {139-142},
   Year = {2008},
   Abstract = {We present a new pass-by-pass gain measurement technique for
             a storage ring FEL. Typically, the FEL oscillator gain is
             obtained by measuring the growth of the envelope of an
             optical macropulse using a slow photo-detector. While
             successfully used for low-gain FEL operation at Duke FEL
             laboratory for many years, this method was not adequate for
             measuring higher gains of distributed optical klystron FELs.
             We have developed a new gain measurement technique based
             upon the direct measurement of the micropulse energy from
             one pass to another using fast photo-detectors. This
             technique provides a powerful tool to study the entire FEL
             gain process, including the startup process of the FEL
             lasing. In this work, we describe this new gain measurement
             technique in detail and compare it with the old technique.
             Using fast photo-detectors with a picosecond time response,
             this new technique can be extended to measure the gain of
             other oscillator FELs, including those driven by
             superconducting linacs.},
   Key = {fds249261}
}

@article{fds249326,
   Author = {Blackston, MA and Ahmed, MW and Perdue, BA and Welller, HR and Bewer, B and Pywell, RE and Wurtz, WA and Igarashi, R and Kucuker, S and Norum, B and Wang, K and Li, J and Mikhailov, SF and Popov, VG and Wu, YK and Sawatzky,
             BD},
   Title = {Erratum: First observation of the splittings of the E1
             p-wave amplitudes in low energy deuteron photodisintegration
             and its implications for the Gerasimov-Drell-Hearn sum rule
             integrand (Physical Review C (2008) 78 (034003))},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {78},
   Number = {6},
   Year = {2008},
   ISSN = {0556-2813},
   url = {http://dx.doi.org/10.1103/PhysRevC.78.069905},
   Doi = {10.1103/PhysRevC.78.069905},
   Key = {fds249326}
}

@article{fds304635,
   Author = {Blackston, MA and Ahmed, MA and Perdue, BA and Weller, HR and Bewer, B and Pywell, RE and Wurtz, WA and Igarashi, R and Kucuker, S and Norum, B and Wang, K and Li, J and Mikhailov, SF and Popov, VG and Wu, YK and Sawatzky,
             BD},
   Title = {First observation of the splittings of the E1 p-wave
             amplitudes in low energy deuteron photodisintegration and
             its implications for the Gerasimov-Drell-Hearn Sum Rule
             integrand},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {78},
   Number = {3},
   Year = {2008},
   ISSN = {0556-2813},
   url = {http://dx.doi.org/10.1103/PhysRevC.78.034003},
   Abstract = {Angular distributions of the cross section and linear
             analyzing powers have been measured for the d(γ→,n)p
             reaction at the High Intensity γ-ray Source with linearly
             polarized beams of 14 and 16 MeV. The outgoing neutrons were
             detected using the Blowfish detector array, consisting of 88
             liquid scintillator detectors with large solid angle
             coverage. The amplitudes of the reduced transition matrix
             elements were extracted by means of fits to the data and
             good agreement was found with a recent potential model
             calculation of the splittings of the triplet p-wave
             amplitudes. The extracted amplitudes are used to reconstruct
             the Gerasimov-Drell-Hearn sum rule integrand for the
             deuteron and are compared to theory. © 2008 The American
             Physical Society.},
   Doi = {10.1103/PhysRevC.78.034003},
   Key = {fds304635}
}

@article{fds292655,
   Author = {MacDowell, AA and Feng, J and Demello, A and Doran, A and Duarte, R and Forest, E and Kelez, N and Marcus, MA and Miller, T and Padmore, HA and Raoux, S and Robin, D and Scholl, A and Schlueter, R and Schmid, P and Stöhr, J and Wan, W and Wei, DH and Wu, Y},
   Title = {Progress on PEEM3 - An aberration corrected X-ray
             photoemission electron microscope at the
             ALS},
   Journal = {AIP Conference Proceedings},
   Volume = {879},
   Pages = {1341-1344},
   Year = {2007},
   Month = {March},
   ISBN = {0735403732},
   ISSN = {0094-243X},
   url = {http://dx.doi.org/10.1063/1.2436312},
   Abstract = {A new ultrahigh-resolution photoemission electron microscope
             called PEEM3 is being developed and built at the Advanced
             Light Source (ALS). An electron mirror combined with a
             much-simplified magnetic dipole separator is to be used to
             provide simultaneous correction of spherical and chromatic
             aberrations. It is installed on an elliptically polarized
             undulator (EPU) beamline, and will be operated with very
             high spatial resolution and high flux to study the
             composition, structure, electric and magnetic properties of
             complex materials. The instrument has been designed and is
             described. The instrumental hardware is being deployed in 2
             phases. The first phase is the deployment of a standard PEEM
             type microscope consisting of the standard linear array of
             electrostatic electron lenses. The second phase will be the
             installation of the aberration corrected upgrade to improve
             resolution and throughput. This paper describes progress as
             the instrument enters the commissioning part of the first
             phase. © 2007 American Institute of Physics.},
   Doi = {10.1063/1.2436312},
   Key = {fds292655}
}

@article{fds141063,
   Author = {Y. Kim and M. D. Busch and P. Wang and W. Wu and Y. K. Wu and J. Choi and I.
             S. Ko and I. S. Park and D. Teytelman},
   Title = {New Generation Digital Longitudinal Feedback System for Duke
             FEL and HIGS Facilities},
   Pages = {518-520},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   Key = {fds141063}
}

@article{fds141045,
   Author = {Y. Kim and J. Li and Y. K. Wu},
   Title = {Growth Time of Longitudinal Coupled Bunch Mode Instability
             in the Duke FEL Facility},
   Pages = {4036-4038},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   Key = {fds141045}
}

@article{fds249314,
   Author = {Li, J and Wang, P and Wu, YK},
   Title = {BPM signal conditioning for a wide range of single-bunch
             current operation in the Duke storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {4042-4044},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096300144&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {The beam position monitor system of the Duke storage ring
             has been in operation since 1998. Recently, by injecting at
             higher energy with a booster synchrotron, the single bunch
             current threshold is much more increased. The high peak
             voltage associated with high single-bunch current degrades
             the performance of the BPM system and can potentially damage
             the BPM electronics. To improve the accuracy of the orbit
             measurement, we carefully studied the BPM signal and found a
             way to overcome this problem. This paper reports our
             findings and presents a solution to condition the signal for
             a wide single-bunch current operation. ©2007
             IEEE.},
   Doi = {10.1109/PAC.2007.4440050},
   Key = {fds249314}
}

@article{fds249315,
   Author = {Popov, V and Busch, M and Hartman, S and Mikhailov, S and Oakeley, O and Wallace, P and Wu, YK},
   Title = {Power supply system for a compact 1.2 GEV booster
             synchrotron},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {521-523},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096301098&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {Low cost power supply system for compact full energy booster
             synchrotron was designed, developed and successfully
             commissioned at Duke University. 500kW second hand thyristor
             controlled power supply has been completely rebuilt to
             provide high accuracy ramping of current in the range
             between 150A and 700A in a 1.3 sec repetition cycle.
             Reproducibility of current at injection and extraction
             energy of better than 0.2% was achieved. Conflict of
             requirements of a fast ramp operation and a magnet
             protection in the case of emergency shutdown was resolved by
             means of additional thyristor switches. All trim power
             supplies involved in ramp have been matched with main power
             supply for the time response and voltage range. Vertical
             injection to and extraction from the booster requires a
             strong Y-bump. Combination of low voltage DC power supply
             and pulse boosting circuit has eliminated the need of
             expensive power supply for peak power about 4 kW. Challenges
             of design, main parameters of the booster power supply
             system and discussion of operation experience are presented
             in this paper. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4440265},
   Key = {fds249315}
}

@article{fds249316,
   Author = {Hartman, SM and Mikhailov, SF and Popov, V and Wu,
             YK},
   Title = {A physics based approach for ramping magnet control in a
             compact booster},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {515-517},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096301096&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {At Duke University, a booster synchrotron was recently
             commissioned as part of the High Intensity Gamma-ray Source
             (HIGS) upgrade. For the ramping magnet power supply
             controls, a scheme was developed to present the high level
             operator interface in terms of the physics quantities of the
             accelerator, i.e. the effective focusing strength of the
             magnets. This scheme allows for the nonlinearities of the
             magnets - a result of the extremely compact footprint of
             this booster - to be incorporated into the low level
             software. This facilitates machine studies and simplifies
             the use of physics modeling. In addition, it simplifies
             operation, allowing the booster to ramp to any energy from
             the 0.24 GeV of the injector linac to the 1.2 GeV maximum of
             the Duke storage ring. The high level of flexibility of this
             system is further advanced by incorporating the level of
             tunability typically found in a storage ring control system.
             Tuning changes made during steady-state operation are
             automatically propagated to the waveforms which make up the
             booster ramp. This approach provides a good match to the
             wide operation modes of the Duke storage ring and its
             associated free electron laser (FEL), and may be useful for
             other compact booster synchrotrons. ©2007
             IEEE.},
   Doi = {10.1109/PAC.2007.4440263},
   Key = {fds249316}
}

@article{fds249317,
   Author = {Huang, S and Li, J and Wu, YK},
   Title = {A direct electron beam energy spread measurement system for
             beam instability and FEL research},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {4045-4047},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096300145&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {One of critical beam parameters for the storage ring based
             light sources is the energy spread of the electron beam. An
             accurate measurement of the energy spread remains a
             challenge. It is well known that the energy spread of the
             electron beam can degrade the spontaneous radiation spectrum
             of an Optical-Klystron (OK) which consists of two wigglers
             separated by a buncher magnet. The reduced modulation in the
             spectrum can be used to determine the energy spread of the
             beam. This paper describes our newly developed energy spread
             measurement system employing a compact and versatile
             spectrometer. This system is used in the beam instability
             research and Free-Electron Laser (FEL) research. In
             particular, by measuring the increase of electron beam
             energy spread we have studied the onset of microwave
             instability. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4440051},
   Key = {fds249317}
}

@article{fds249318,
   Author = {Wu, YK and Li, J and Popov, V and Mikhailov, SF and Wang,
             P},
   Title = {A tune measurement system for lowcurrent and energy ramping
             operation of a booster synchrotron},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {4063-4065},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096300148&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {A betatron tune measurement system is one of the most
             important diagnostic tools for any circular accelerator. For
             the commissioning of a booster synchrotron newly developed
             for top-off injection into the Duke storage ring, a
             versatile tune measurement system employing a network
             analyzer, a short stripline kicker, a space filter and a
             photomultiplier tube has been developed to allow tune
             measurements over a wide range of beam energies from 0.24 to
             1.2 GeV, and for low current measurements at a few
             micro-amperes. The signal from the highly sensitive optical
             detection system is also used for fast tune measurements
             with a realtime oscilloscope. This technique is being
             developed for live tune monitoring during booster energy
             ramping. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4440054},
   Key = {fds249318}
}

@article{fds249319,
   Author = {Kim, Y and Wu, W and Busch, M and Wang, P and Wu, YK and Teytelman, D and Park, I-S and Ko, IS},
   Title = {New generation digital longitudinal feedback system for Duke
             FEL and HIγS facilities},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {518-520},
   Year = {2007},
   url = {http://dx.doi.org/10.1109/PAC.2007.4440264},
   Abstract = {To cure harmful longitudinal coupled-bunch mode beam
             instabilities during high-current and multi-bunch beam
             operations at the Duke Free Electron Laser (FEL) and High
             Intensity γ-ray Source (HIγS) facilities, we have been
             developing a new generation digital bunch-by-bunch
             longitudinal feedback (LFB) system which is based on an
             Integrated Gigasample Processor (iGp-64F). In this paper, we
             describe the new generation digital longitudinal feedback
             system for the Duke FEL and HIγS facilities. ©2007
             IEEE.},
   Doi = {10.1109/PAC.2007.4440264},
   Key = {fds249319}
}

@article{fds249320,
   Author = {Sun, C and Wu, YK},
   Title = {The feasibility study of measuring the polarization of a
             relativistic electron beam using a compton scattering
             gamma-ray source},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {4057-4059},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096300147&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {The Compton scattering of a circularly polarized photon beam
             and a polarized electron beam leads to an asymmetric spatial
             distribution of the gamma rays. This asymmetry has been
             calculated for the High Intensity Gamma-ray Source (HIGS)
             beam at Duke University. Owing to the high intensity of the
             HIGS beam, this asymmetry is determined to be measurable
             with a small statistical error using a simple optical
             imaging system for gamma-ray beams. We propose to set up
             this system to measure the polarization of the electron beam
             in the Duke storage ring. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4440053},
   Key = {fds249320}
}

@article{fds249321,
   Author = {Wu, YK},
   Title = {Accelerator physics research and light source development
             programs at Duke University},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {1215-1217},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096304074&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {The Duke Free-Electron Laser Laboratory (DFELL) has recently
             completed two major accelerator/light source development
             projects - we successfully commissioned the world's first
             distributed optical klystron FEL (DOK-1 FEL) and a new 0.24
             - 1.2 GeV booster synchrotron. The DOK-1 FEL has a much
             improved FEL gain compared with two-wiggler optical
             klystrons. This allows the DOK-1 FEL to become a versatile
             light source for UV-VUV operation and as a driver for a
             high-flux Compton gamma-source. The top-off booster injector
             for the Duke storage ring is part of the upgrade project of
             High Intensity Gamma-ray Source (HIGS), a facility jointly
             developed by the DFELL and Triangle Universities Nuclear
             Laboratory. The accelerator and light source development has
             created new opportunities for accelerator physics research.
             In this paper, we will report our recent progress in
             accelerator and light source development as well as the
             ongoing accelerator physics research programs at the DFELL.
             ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4441034},
   Key = {fds249321}
}

@article{fds249322,
   Author = {Li, J and Mikhailov, SF and Huang, S and Popov, V and Wu,
             YK},
   Title = {Compensation of the beam dynamics effects caused by the
             extraction Lambertson septum of the HIGS
             booster},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {3582-3584},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096302069&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {As part of the High Intensity Gamma-Ray Source (HIGS)
             upgrade, the booster synchrotron has been built and
             commissioned in 2006. It ramps the electron beam between
             0.24 and 1.2 GeV for top-off injection into the Duke storage
             ring. The booster has vertical injection/extraction which
             uses symmetrical schemes with a bumped orbit. The
             injection/extraction kickers and corresponding septum
             magnets are located in the opposite straight sections of the
             booster ring separated by about 1/4 of the vertical betatron
             wave. Due to the non-ideal properties of the magnetic
             material, the magnetic field leaks out into the stored beam
             chamber, which results in orbit distortion, tune and
             chromaticity shifts, and change of coupling. The dynamics
             impacts due to the leaked septum fields have been
             successfully compensated to achieve good injection
             efficiency. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4440499},
   Key = {fds249322}
}

@article{fds249323,
   Author = {Mikhailov, SF and Wu, YK and Li, J and Popov, VG and Hartman,
             SM},
   Title = {Challenges for energy ramping in a compact booster
             synchrotron},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {1212-1214},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096304073&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {A booster synchrotron has been recently commissioned at Duke
             University FEL Laboratory as a part of the High Intensity
             Gamma-ray Source (HIGS) facility. The booster provides
             top-off injection into the storage ring in the energy range
             of 0.24 - 1.2 GeV. In order to minimize the cost of the
             project, the booster is designed with a very compact
             footprint. As a result, unconventionally high field bending
             magnets at 1.76 T are required. A main ramping power supply
             drives all dipoles and quadrupoles. Quadrupole trims are
             used to compensate for tune changes caused by the change of
             relative focusing strength during ramping. Sextupoles
             compensate for chromatic effects caused by dipole magnet
             pole saturation. All these compensations have to be
             performed as a function of beam energy. Above 1.1 GeV, where
             the magnets are heavily saturated, the reduction of dynamic
             aperture is compensated by redistribution of strength among
             the sextupole families. With these compensations, effects of
             the magnet saturation do not cause any considerable beam
             loss during injection, energy ramping, and extraction.
             ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4441033},
   Key = {fds249323}
}

@article{fds249324,
   Author = {Popov, V and Busch, M and Hartman, S and Li, J and Mikhailov, S and Wallace, P and Wang, P and Wu, YK and Kurkin, GY},
   Title = {Electron beam diagnostics for compact 1.2 GEV booster
             synchrotron},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {4051-4053},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   url = {http://dx.doi.org/10.1109/PAC.2007.4440052},
   Abstract = {First operational experience has been gained with the linac
             and booster diagnostic system during the commissioning of
             the booster synchrotron at Duke University. The booster was
             designed and developed as an injector for the storage ring
             as a part of the High Intensity Gamma-ray Source (HIGS)
             upgrade of Duke FEL storage ring. Booster beam
             instrumentation includes: beam charge measurements (Faraday
             cups, Integrated Current Transformers (ICT), Modular
             Parametric Current Transformer (MPCT)), beam position
             monitoring (BPM), betatron tune measurements using
             synchrotron radiation (SR), transverse profile and temporal
             beam structure monitoring (insertable screens, striplines,
             dissector). The diagnostics provided good understanding of
             electron beam behavior and allowed us to adjust important
             beam parameters within design specifications. An overview of
             the diagnostic instrumentation of the Duke Booster
             synchrotron is given along with measurement examples and
             discussion of operational experience. ©2007
             IEEE.},
   Doi = {10.1109/PAC.2007.4440052},
   Key = {fds249324}
}

@article{fds249332,
   Author = {Tonchev, AP and Angell, C and Boswell, M and Chyzh, A and Howell, CR and Karwowski, HJ and Kelley, JH and Tornow, W and Tsoneva, N and Wu,
             YK},
   Title = {Study of collective dipole excitations below the giant
             dipole resonance at HIγS},
   Journal = {AIP Conference Proceedings},
   Volume = {891},
   Pages = {339-347},
   Year = {2007},
   ISSN = {0094-243X},
   url = {http://dx.doi.org/10.1063/1.2713535},
   Abstract = {The High-Intensity Gamma-ray Source utilizing intra-cavity
             back-scattering of free electron laser photons from
             relativistic electrons allows one to produce a unique beam
             of high-flux gamma rays with 100% polarization and
             selectable energy and energy resolution which is ideal for
             low-energy γ-ray scattering experiments. Nuclear resonance
             fluorescence experiments have been performed on N=82 nuclei.
             High sensitivity studies of E1 and M1 excitations at
             energies close to the neutron emission threshold have been
             performed. The method allows the determination of excitation
             energies, spin, parities, and decay branching ratios of the
             pygmy dipole mode of excitation. The observations are
             compared with calculations using statistical and
             quasi-particle random-phase approximations. © 2007 American
             Institute of Physics.},
   Doi = {10.1063/1.2713535},
   Key = {fds249332}
}

@article{fds249333,
   Author = {Mikhailov, SF and Busch, MD and Emamian, M and Hartman, SM and Kim, Y and Li, J and Popov, VG and Swift, G and Wallace, PW and Wang, P and Wu, YK and Howell, CR and Gavrilov, NG and Kurkin, GY and Matveev, Y and Anchugov,
             OV and Shvedov, DA and Vinokurov, NA},
   Title = {Commissioning of the booster injector synchrotron for the
             HIGS facility at Duke University},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {1209-1211},
   Booktitle = {Proceedings of 2007 Particle Accelerator
             Conference},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096304072&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {A booster synchrotron (Duke booster) has been built and
             recently commissioned at Duke University Free Electron Laser
             Laboratory (DFELL) as part of the High Intensity Gamma-ray
             Source (HIGS) facility upgrade. HIGS is collaboration
             between the DFELL and Triangle Universities Nuclear
             Laboratory (TUNL). The booster provides top-off injection
             into the Duke FEL storage ring in the energy range of 0.24 -
             1.2 GeV. When operating the Duke storage ring to produce
             high energy Compton gamma ray beams above 20 MeV, continuous
             electron beam loss occurs. The lost electrons are
             replenished by the booster injector operating in the top-off
             mode. The presentt operational injection and extraction rate
             of the machine allows us to routinely replenish up to 5·10
             8 electrons per second. The compactness of the booster posed
             a challenge for its development and commissioning. The
             booster has been successfully commissioned in 2006. This
             paper reports experience of commissioning and initial
             operation of the booster. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4441032},
   Key = {fds249333}
}

@article{fds249336,
   Author = {Kim, Y and Li, J and Wu, Y},
   Title = {Growth time of the longitudinal coupled bunch mode beam
             instability at the Duke FEL facility},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Pages = {4036-4038},
   Year = {2007},
   ISBN = {978-1-4244-0916-7},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000255096300143&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {To determine the required power of an amplifier for the
             longitudinal feedback (LFB) system, the growth time of the
             strongest longitudinal coupled bunch mode instability (CBMI)
             in the Duke storage ring should be measured in advance. In
             2005, we measured strength of the strongest longitudinal
             beam instability in the Duke storage ring with four and
             eight symmetrically filled buckets. By analyzing measured
             data, the growth time of the strongest dipole mode of the
             longitudinal CBMI in the Duke storage ring can be estimated.
             At a beam energy of 274 MeV, the growth time is about 0.365
             ms for a total stored beam current of 160 mA. From the
             measured growth time, we estimated the required power of the
             amplifier for the LFB system. To damp all harmful
             longitudinal CBMIs with an energy deviation of 0.1% (rms)
             within its growth time of 0.365 ms, we have to supply about
             110 W (rms) to an LFB kicker whose a central frequency is
             937.3875 MHz. In this paper, we describe the growth time of
             the longitudinal CBMI at the Duke storage ring and the
             estimation of the required power for the LFB system to damp
             all CBMIs within 0.365 ms. ©2007 IEEE.},
   Doi = {10.1109/PAC.2007.4440049},
   Key = {fds249336}
}

@article{fds249366,
   Author = {Wu, YK and Vinokurov, NA and Mikhailov, S and Li, J and Popov,
             V},
   Title = {High-gain lasing and polarization switch with a distributed
             optical-klystron free-electron laser.},
   Journal = {Physical Review Letters},
   Volume = {96},
   Number = {22},
   Pages = {224801},
   Year = {2006},
   Month = {June},
   ISSN = {0031-9007},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/16803315},
   Abstract = {This Letter reports the first experimental results from the
             world's first distributed optical-klystron (DOK)
             free-electron laser (FEL), the DOK-1 FEL, at Duke
             University. The DOK-1 FEL is a hybrid system, comprised of
             four wigglers: two horizontal and two helical. With the
             DOK-1 FEL, we have obtained the highest FEL gain among all
             storage ring based FELs at 47.8% (+/-2.7%) per pass. We have
             also demonstrated that the FEL gain can be enhanced by
             increasing electron bunching using wigglers with a different
             polarization. Furthermore, we have realized controlled
             polarization switches of the FEL beam by a nonoptical means
             through the manipulation of a buncher magnet.},
   Doi = {10.1103/PhysRevLett.96.224801},
   Key = {fds249366}
}

@article{fds249313,
   Author = {Werner, V and Pietralla, N and Brentano, PV and Kneissl, U and Pitz, HH and Tonchev, A and Ahmed, MW and Fransen, C and Garrel, HV and Kohstall, C and Li, J and Linnemann, A and Müller, S and Pinayev, IV and Savran, D and Scheck, M and Stedile, F and Tornow, W and Walter, S and Weller, HR and Wu,
             YK},
   Title = {New findings for mixed-symmetry states},
   Journal = {AIP Conference Proceedings},
   Volume = {819},
   Pages = {340-344},
   Booktitle = {AIP Conf.Proc.},
   Editor = {A.Woehr, A.Aprahamian},
   Year = {2006},
   ISSN = {0094-243X},
   url = {http://dx.doi.org/10.1063/1.2187881},
   Abstract = {This report summarizes experiments performed on 164Dy using
             photon scattering techniques. The scissors mode in 164Dy has
             been reinvestigated using unpolarized photons from
             bremsstrahlung and polarized photons from a free electron
             laser. The current experiments lead to the observation of a
             new decay mode of the scissors mode in well-deformed rotors.
             © 2006 American Institute of Physics.},
   Doi = {10.1063/1.2187881},
   Key = {fds249313}
}

@article{fds249363,
   Author = {Li, TC and Pietralla, N and Tonchev, AP and Ahmed, MW and Ahn, T and Angell, C and Blackston, MA and Costin, A and Keeter, KJ and Li, J and Lisetskiy, A and Mikhailov, S and Parpottas, Y and Perdue, BA and Rainovski, G and Tornow, W and Weller, HR and Wu,
             YK},
   Title = {First evidence for spin-flip M1 strength in
             Ar40},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {73},
   Number = {5},
   Pages = {054306},
   Year = {2006},
   ISSN = {0556-2813},
   url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000073000005054306000001&idtype=cvips&gifs=yes},
   Abstract = {The Ar40(γ→,γ′) photon scattering reaction was used to
             search for spin-flip M1 strength in Ar40. The nearly
             monochromatic, linearly polarized photon beam of HIγS, in
             an energy region from 7.7 to 11 MeV, was employed in this
             study. 28 dipole excitations were observed. The azimuthal
             intensity asymmetry indicated that all of these states were
             E1 except for the state at Ex=9.757 MeV. Shell-model
             calculations were used to interpret this state as one
             fragment of the spin-flip M1 strength in Ar40. © 2006 The
             American Physical Society.},
   Doi = {10.1103/PhysRevC.73.054306},
   Key = {fds249363}
}

@article{fds43902,
   Author = {Y. K. Wu and J. Li and J. Wu},
   Title = {Observations and Measurements of Anomalous Hollow Electron
             Beams in a Storage Ring},
   Journal = {Proceedings of Particle Accelerator Physics 2005, Knoxville,
             TN, 2005},
   Pages = {3082-3084},
   Year = {2005},
   Month = {May},
   Abstract = {Anomalous hollow electron beams have been recently observed
             in the Duke storage ring. With a single bunch beam in a
             lattice with a negative chromaticity, a hollow beam can be
             created. This beam consists of a solid core beam inside and
             a large ring beam outside. In this paper, we report the
             measurements of the hollow beam phenomenon, including its
             distinct image pattern and spectrum signature, and its
             evolution with time. By capturing the post-instability
             bursting beam, the hollow beam is a unique model system for
             studying transverse instabilities, in particular, the
             interplay of the wakefield and lattice nonlinearity. The
             hollow beam can also be used as a tool to study linear and
             nonlinear particle dynamics in the storage
             ring.},
   Key = {fds43902}
}

@article{fds43901,
   Author = {Y. K. Wu and Matthew D. Busch and Mark Emamian and Joe Faircloth and J.
             Gustavsson, Steven M. Hartman and C. Howell and M. Johnson and Jingyi
             Li, Stepan Mikhailov and Owen Oakeley and J. Patterson and Maurice
             Pentico, Victor Popov and V. Rathbone and Gary Swift and Patrick
             Walter Wallace and Ping},
   Title = {Recommissioning of Duke Storage Ring with a HOM-Damped RF
             Cavity and a New Straight Section Lattice for
             FELs},
   Journal = {Proceedings of Particle Accelerator Confernece 2005,
             Knoxville, TN, 2005},
   Pages = {3934-3936},
   Year = {2005},
   Month = {May},
   Abstract = {The Duke FEL lab operates a unique UV/VUV storage ring FEL
             and an FEL driven nearly monochromatic, highly polarized,
             high intensity Compton gamma-ray source. The Duke storage
             ring light source is undergoing several phases of upgrade in
             order to significantly improve its light source capabilities
             and performance. The recent upgrade in 2004 included an
             upgrade of the RF system with a high-order mode damped RF
             cavity and a new 34 meter long straight section lattice
             designed to host new FEL wigglers. This upgrade was
             completed in August 2004, followed by the storage ring and
             light source commissioning. This paper provides an overview
             of this upgrade project and reports the commissioning
             experience of the Duke storage ring and light
             sources.},
   Key = {fds43901}
}

@article{fds249365,
   Author = {Wu, YK and Li, J and Wu, J},
   Title = {Anomalous hollow electron beams in a storage
             ring.},
   Journal = {Physical Review Letters},
   Volume = {94},
   Number = {13},
   Pages = {134802},
   Year = {2005},
   Month = {April},
   ISSN = {0031-9007},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/15903998},
   Abstract = {This Letter reports the first observations of an anomalous
             hollow electron beam in the Duke storage ring. Created by
             exciting the single-bunch beam in a lattice with a negative
             chromaticity, the hollow beam consists of a solid core
             inside and a large ring outside. We report the detailed
             measurements of the hollow beam phenomenon, including its
             distinct image pattern, spectrum signature, and its
             evolution with time. By capturing the postinstability
             bursting beam, the hollow beam is a unique model system for
             studying the transverse instabilities, in particular, the
             interplay of the wakefield and the lattice nonlinearity. In
             addition, the hollow beam can be used as a powerful tool to
             study the linear and nonlinear particle dynamics in the
             storage ring.},
   Doi = {10.1103/PhysRevLett.94.134802},
   Key = {fds249365}
}

@article{fds44056,
   Author = {Vaclav Vylet and Patrick W. Wallace and Y. K.
             Wu},
   Title = {Towards the Top-off Mode at the Duke Free Electron Laser
             Laboratory},
   Journal = {JASRI/SPring-8 Report A 2005-02, Proceedings of the 3rd
             workshop on radiation safety of synchrotron radiation
             sources},
   Year = {2005},
   Key = {fds44056}
}

@article{fds249259,
   Author = {Wu, YK and Mikhailov, S and Li, J and Popov, V and Vinokurov, NA and Gavrilov, NG and Shevchenko, OA and Vobly, PD and Kulipanov,
             GN},
   Title = {First lasingand initial operation ofa circularly polarized
             optical klystron ok-5 felandavariably polarized distributed
             optical klystron DOK-1 FEL at DUKE},
   Journal = {Proceedings of the 27th International Free Electron Laser
             Conference, FEL 2005},
   Pages = {407-410},
   Year = {2005},
   Abstract = {To improve the capability and performance of its light
             sources, the Duke FEL lab (DFELL) is upgrading its storage
             ring based FEL. The existing linearly polarized OK-4 FEL
             wigglers are being replaced gradually by the next generation
             OK-5 wigglers capable of producing either linearly or
             circularly polarized light. In the second phase of this
             upgrade in 2005, the OK-5 FEL consisting of two wigglers is
             installed together with the OK-4 FEL in a specially designed
             magnetic lattice. The circularly polarized OK-5 FEL was
             first brought to lasing on Aug. 14, 2005. In the following
             days, the first distributed optical klystron FEL with
             variable polarization, the DOK-1 FEL, comprised of two
             horizontal OK-4 wigglers and two circular OK-5 wigglers, was
             brought to lasing for the first time. In this paper, we
             report our commissioning experience and initial measurements
             of both the OK-5 FEL and DOK-1 FEL.},
   Key = {fds249259}
}

@article{fds249304,
   Author = {Kurkin, G and Pinaev, I and Hartman, S and Mikhailov, S and Wu,
             Y},
   Title = {A new timing system for the Duke booster and storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {3159-3160},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1591398},
   Abstract = {A dedicated booster synchrotron is being constructed at the
             Duke FEL Laboratory to provide full energy injection into
             the main electron storage ring. A new timing system has been
             developed to coordinate the injection of electron bunches
             from the linac to the booster, the ramping of energy in the
             booster, and extraction of bunches into the main ring. The
             timing system will allow the extraction of any bunch in the
             booster into any selected bucket in the main ring to provide
             top-off injection for any of the various operational bunch
             patterns of the main ring. A new master oscillator has also
             been developed for the RF system of the booster. The
             oscillator may be tuned independently or phase-locked to the
             master oscillator of the main ring. The issues of the soft
             phase locking process of the new master oscillator are
             discussed. The timing system and new oscillator have been
             fabricated and tested and are ready for operation. © 2005
             IEEE.},
   Doi = {10.1109/PAC.2005.1591398},
   Key = {fds249304}
}

@article{fds249305,
   Author = {Wu, YK and Li, J and Wu, J},
   Title = {Observations and measurements of anomalous hollow electron
             beams in the duke storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {3082-3084},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1591371},
   Abstract = {Anomalous hollow electron beams have been recently observed
             in the Duke storage ring. With a single bunch beam in a
             lattice with a negative chromaticity, a hollow beam can be
             created. This beam consists of a solid core beam inside and
             a large ring beam outside. In this paper, we report the
             measurements of the hollow beam phenomenon, including its
             distinct image pattern and spectrum signature, and its
             evolution with time. By capturing the post-instability
             bursting beam., the hollow beam is a unique model system for
             studying transverse instabilities, in particular, the
             interplay of the wakefield and lattice nonlinearity. The
             hollow beam can also be used as a tool to study linear and
             nonlinear particle dynamics in the storage ring. © 2005
             IEEE.},
   Doi = {10.1109/PAC.2005.1591371},
   Key = {fds249305}
}

@article{fds249306,
   Author = {Hartmant, SM and Mikhailov, SF and Wu, YK},
   Title = {A control system for the duke booster synchrotron},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {3792-3794},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1591620},
   Abstract = {The Duke Free Electron Laser Laboratory is developing a
             booster synchrotron to provide full energy injection into
             the Duke electron storage ring. In this paper, we describe
             the development of the control system for the booster.
             Requirements include the competing needs of simple and
             reliable turn-key operation for the machine as a booster;
             and the sophistication and flexibility of operation of the
             machine as a storage ring for commissioning, machine studies
             and as a light source. To simplify operations and machine
             studies, the high level controls will present the system in
             terms of the physics quantities of the accelerator, allowing
             a tight integration between the physics model and the low
             level hardware control, as we have previously implemented
             for the Duke storage ring. © 2005 IEEE.},
   Doi = {10.1109/PAC.2005.1591620},
   Key = {fds249306}
}

@article{fds249307,
   Author = {Steier, C and Robin, D and Decking, W and Laskar, J and Nadolski, L and Wu,
             Y},
   Title = {Measuring and understanding the momentum aperture in a
             storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {645-649},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1590514},
   Abstract = {The momentum aperture of a storage ring is a very important
             parameter that strongly influences the performance,
             especially the beam lifetime. For the special case of
             synchrotron light sources with small emittance like the
             Advanced Light Source (ALS), the momentum aperture depends
             strongly on the transverse dynamics. It is very sensitive to
             machine conditions such as the tunes, chromaticities,
             lattice symmetry, and spurious coupling, since depending on
             those conditions the Touschek scattered particles explore
             different resonance regions in the phase space. In light
             sources, the momentum aperture usually also depends strongly
             on the vertical physical aperture. Applying frequency
             analysis techniques in simulations and for turnby-turn orbit
             measurement data provides a very powerful tool to measure
             and understand limitations of the dynamic momentum aperture.
             The techniques presented are applicable to other light
             sources, as well as damping rings and many types of
             colliders. © 2005 IEEE.},
   Doi = {10.1109/PAC.2005.1590514},
   Key = {fds249307}
}

@article{fds249308,
   Author = {Li, J and Wu, YK and Sun, C},
   Title = {Improved long radius of curvature measurement system for FEL
             mirrors},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {1787-1789},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1590913},
   Abstract = {The 53.73 meter long Duke free electron laser (FEL) cavity
             consists of two concave mirrors with radius of curvature
             longer than 27 meters. A proper radius of curvature is
             designed to achieve an optimal and stable operation of the
             FEL. This requires accurate measurements of the cavity
             mirror's radius of curvature before its initial
             installation. Subsequent radius of curvature measurements
             are performed to ensure no significant deformation of the
             mirror occurs after a period of extensive use. A direct
             measurement based upon the geometric optics principles has
             been used at Duke PEL Lab (DFELL) for years. Recently, we
             have significantly upgraded this measurement apparatus by
             utilizing a He-Ne laser as the light source and a straight
             wire with a proper size as the object. In this paper we
             describe the details of the measurement setup and report the
             benefits of the recent upgrades. In addition, we report the
             improved data analysis technique and results of recent long
             radius of curvature measurements. © 2005
             IEEE.},
   Doi = {10.1109/PAC.2005.1590913},
   Key = {fds249308}
}

@article{fds249309,
   Author = {Popov, VG and Hartman, S and Mikhailov, SF and Oakeley, O and Wallace,
             P and Wu, YK},
   Title = {3 KA power supplies for the Duke OK-5 FEL
             wigglers},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {3901-3903},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1591662},
   Abstract = {The next generation electromagnetic OK-5/Duke storage ring
             FEL wigglers [1], [2] require three 3kA/70V power supplies
             with current stability about 20 ppm and current ripples less
             than 20 ppm in their full operating range. Duke FEL
             Laboratory acquired three out-of-service SCR controlled
             power supplies (Trans-Rex, 5kA/100V), which were built
             almost 30 years ago. The existing archaic firing circuit,
             lack of any output voltage filtering and with an outdated
             DCCT, would not be able to meet the above requirements. To
             deliver the desirable high performance with very limited
             funds, all three Trans-Rex power supplies have been
             completely rebuilt in-house at DFELL. Modern high stability
             electronic components and a high precision Danfysik DCCT
             have been used. A new symmetrical firing circuit, efficient
             passive filter and reliable transformer-coupled active
             filter are used to reduce output current ripples to an
             appropriate level. At the present time, all three
             refurbished power supplies are in operation. One of these
             power supplies was used since August, 2004 to feed OK-4
             wigglers with good overall performance. Others two have been
             tested and used as power supplies for magnetic measurements.
             © 2005 IEEE.},
   Doi = {10.1109/PAC.2005.1591662},
   Key = {fds249309}
}

@article{fds249310,
   Author = {Busch, M and Mikhailov, S and Emamian, M and Faircloth, J and Hartman,
             S and Li, J and Popov, V and Swift, G and Vylet, V and Wallace, P and Wang, P and Wu, Y and Gavrilov, N and Kurkin, G and Matveev, Y and Shvedov, D and Anchugov, O and Vinokurov, N},
   Title = {Status of the booster injector for the duke fel storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {3544-3546},
   Year = {2005},
   ISBN = {0-7803-8859-3},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000235745200074&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {This paper presents the current status of the booster
             synchrotron for the Duke Free Electron Laser Laboratory
             (DFELL) storage ring. The booster will provide full energy
             injection into the storage ring in a wide energy range from
             0.27 to 1.2 GeV. When operating the DFELL storage ring as
             the High Intensity Gamma Source (HIGS) to produce gamma
             photons above 20 MeV with Compton scattering, continuous
             electron loss occurs. The top-off mode operation of the
             booster injector will enable the continuous operation of the
             HIGS facility by replenishing the lost electrons. The design
             requirement for a compact booster with the single bunch
             extraction capability remains a challenge for the machine
             development. Presently, the booster project is in the
             installation phase. The magnetic elements, vacuum chambers,
             injection and extraction kickers have been developed in
             collaboration with and fabricated at the Budker Institute of
             Nuclear Physics (BINP), Russia. The diagnostic and control
             system is being developed at DFELL. The commissioning of the
             booster synchrotron will start at the end of 2005. © 2005
             IEEE.},
   Doi = {10.1109/PAC.2005.1591533},
   Key = {fds249310}
}

@article{fds249311,
   Author = {Arbuzov, VS and Bushuev, A and Gavrilov, N and Gorniker, EI and Kenjebulatov, E and Kholopov, MA and Kondakov, AA and Krutikhin, SA and Kruchkov, YG and Kuptsov, IV and Kurkin, GY and Mironenko, LA and Mityanina, N and Motygin, SV and Osipov, VN and Petrov, V and Pilan, AM and Popov, AM and Rotov, E and Sedlyarov, I and Tribendis, AG and Volkov, V and Wang, P and Mikhailov, S and Wallace, PW and Wu, YK},
   Title = {Commissioning of the new RF system with the HOM damped RF
             cavity},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {1555-1556},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1590833},
   Abstract = {A new 178 MHz RF system has been commissioned at Duke
             Storage Ring. It consists of a 140 kW tetrode transmitter;
             higher order modes (HOM) damped RF cavity and the necessary
             frequency and voltage control electronics. The cavity walls
             are made of copper-on-stainless steel bimetal (8 mm Cu, 7 mm
             SS). The cavity has a larger beam pipe opening (700 mm in
             diameter) in the down-stream side, which allows the HOM
             propagating out of the cavity and being absorbed by the
             ceramic loads. The design details and the commissioning
             results are presented in this paper. © 2005
             IEEE.},
   Doi = {10.1109/PAC.2005.1590833},
   Key = {fds249311}
}

@article{fds249312,
   Author = {Popov, VG and Hartman, and Mikhailov, SF and Oakely, O and Wallace, P and Wu, YK},
   Title = {Trim power supplies for the Duke booster and storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2005},
   Pages = {3919-3921},
   Year = {2005},
   url = {http://dx.doi.org/10.1109/PAC.2005.1591668},
   Abstract = {The on-going Duke storage ring upgrades and the development
             of a new booster synchrotron injector require more than 100
             units of high performance unipolar and bipolar trim power
             supplies in the current range of -15 A to +15 A. However,
             most of the trim power supplies on the market do not deliver
             two critical performance features simultaneously: a high
             current stability and a low current noise. An in-house trim
             power supply development program has been put in force to
             design, fabricate, and test low cost linear power supplies
             with current stability about 100 ppm and current ripples
             less than 100 ppm in a broad band. A set of unipolar power
             supplies (0-12 A) have been designed, fabricated and
             successfully tested. Since August, 2004 they have been used
             in storage ring operation with excellent performance. The
             prototype of bipolar power supplies (±15 A) has been
             designed and tested as well. The main design principles and
             the performance results of both unipolar and bipolar
             supplies have been presented in this paper. © 2005
             IEEE.},
   Doi = {10.1109/PAC.2005.1591668},
   Key = {fds249312}
}

@article{fds249330,
   Author = {Tornow, W and Esterline, JH and Howell, CR and Karwowski, HJ and Kelley,
             JH and Tonchev, AP and Li, J and Mikhailov, SF and Pinayev, IV and Wu, YK and Weisel, GJ and Witała, H},
   Title = {Photon analyzing power for the three-body breakup of
             3He at Eγ = 15.0 MeV},
   Journal = {AIP Conference Proceedings},
   Volume = {768},
   Pages = {138-140},
   Year = {2005},
   ISSN = {0094-243X},
   url = {http://dx.doi.org/10.1063/1.1932890},
   Abstract = {Photon analyzing power for the three-body breakup of 3He has
             been studied at Eγ = 15.0 MeV. The measurements were done
             at the HIγS facility at Duke University. © 2005 American
             Institute of Physics.},
   Doi = {10.1063/1.1932890},
   Key = {fds249330}
}

@article{fds249331,
   Author = {Tonchev, AP and Boswell, M and Howell, CR and Karwowski, HJ and Kelley,
             JH and Tornow, W and Wu, YK},
   Title = {The high intensity γ-ray source (HIγS) and recent
             results},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             B: Beam Interactions with Materials and Atoms},
   Volume = {241},
   Number = {1-4},
   Pages = {170-175},
   Year = {2005},
   ISSN = {0168-583X},
   url = {http://dx.doi.org/10.1016/j.nimb.2005.07.080},
   Abstract = {The high intensity γ-ray source (HIγS) utilizes
             intra-cavity backscattering of free electron laser photons
             from the Duke electron storage ring to produce a unique
             monoenergetic beam of high-flux γ-rays with high
             polarization and selectable energy resolution. At present,
             γ-ray beams with energies from 2 to 58 MeV are available
             with intensities as high as 10 5-5 × 106 γ/s, energy
             spreads of 3% or better, and nearly 100% linear
             polarization. The quality and intensity of the γ-ray beams
             at HIγS are responsible for the unprecedented performance
             of this facility in a broad range of research programs in
             nuclear structure, nuclear astrophysics and nuclear
             applications. Recent results from excitation of isomeric
             states in (γ, n) reactions and parity assignments of dipole
             states determined via the (γ, γ′) reaction are
             presented. © 2005 Elsevier B.V. All rights
             reserved.},
   Doi = {10.1016/j.nimb.2005.07.080},
   Key = {fds249331}
}

@article{fds249364,
   Author = {Savran, D and Müller, S and Zilges, A and Babilon, M and Ahmed, MW and Kelley, JH and Tonchev, A and Tornow, W and Weller, HR and Pietralla, N and Li, J and Pinayev, IV and Wu, YK},
   Title = {Parity assignments in 172,174Yb using polarized
             photons and the K quantum number in rare earth
             nuclei},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {71},
   Number = {3},
   Pages = {034304},
   Year = {2005},
   ISSN = {0556-2813},
   url = {http://hdl.handle.net/10161/11080 Duke open
             access},
   Abstract = {The 100% polarized photon beam at the high intensity γ ray
             source (HIγS) at Duke University has been used to determine
             the parity of six dipole excitations between 2.9 and 3.6 MeV
             in the deformed nuclei 172,174Yb in photon scattering (γ
             →, γ′) experiments. The measured parities are compared
             with previous assignments based on the K quantum number that
             had been assigned in nuclear resonance fluorescence (NRF)
             experiments by using the Alaga rules. A systematic survey of
             the relation between γ-decay branching ratios and parity
             quantum numbers is given for the rare earth nuclei. © 2005
             The American Physical Society.},
   Doi = {10.1103/PhysRevC.71.034304},
   Key = {fds249364}
}

@article{fds249381,
   Author = {Schmid, P and Feng, J and Padmore, H and Robin, D and Rose, H and Schlueter, R and Wan, W and Forest, É and Wu, Y},
   Title = {Correction and alignment strategies for the beam separator
             of the photoemission electron microscope 3
             (PEEM3)},
   Journal = {Review of Scientific Instruments},
   Volume = {76},
   Number = {2},
   Pages = {023302-1-023302-14},
   Year = {2005},
   ISSN = {0034-6748},
   url = {http://dx.doi.org/10.1063/1.1841871},
   Abstract = {A high-resolution aberration-corrected photoemission
             electron microscope (PEEM3) will be installed on an
             undulator beamline at the Advanced Light Source at the
             Lawrence Berkeley National Laboratory. The aim of this
             instrument is to provide a substantial flux and resolution
             improvement by employing an electron mirror for correcting
             both the third-order spherical aberration and the primary
             chromatic aberration. In order to utilize this concept of
             correction, a beam separator is a prerequisite. Crucial to
             achieving a resolution of 5 nm for the high-resolution mode,
             and a 16-fold increase in throughput at the same resolution
             as its predecessor, PEEM2, specified as 20 nm at 2%
             transmission, for the high flux mode is the double-symmetric
             design of the beam separator, which eliminates all the
             second-order geometric aberrations. Nonetheless, substantial
             tuning capabilities must be incorporated into the PEEM3
             design to compensate for both systematic and random errors.
             In this article, we investigate how to correct for
             nonsystematic imperfections and for systematic uncertainties
             in the accuracy of the magnetic fields and focus on how
             degradation of the resolution and the field of view can be
             minimized. Finally, we outline a tentative correction
             strategy for PEEM3. © 2005 American Institute of
             Physics.},
   Doi = {10.1063/1.1841871},
   Key = {fds249381}
}

@article{fds249384,
   Author = {Feng, J and Forest, E and MacDowell, AA and Marcus, M and Padmore, H and Raoux, S and Robin, D and Scholl, A and Schlueter, R and Schmid, P and Stöhr, J and Wan, W and Wei, DH and Wu, Y},
   Title = {An x-ray photoemission electron microscope using an electron
             mirror aberration corrector for the study of complex
             materials},
   Journal = {Journal of Physics Condensed Matter},
   Volume = {17},
   Number = {16},
   Pages = {S1339-S1350},
   Year = {2005},
   url = {http://www.iop.org/EJ/abstract/0953-8984/17/16/005},
   Abstract = {A new ultrahigh-resolution photoemission electron microscope
             called PEEM3 is being developed at the advanced light source
             (ALS). An electron mirror combined with a sophisticated
             magnetic beam separator is used to provide simultaneous
             correction of spherical and chromatic aberrations. Installed
             on an elliptically polarized undulator beamline, PEEM3 will
             be operated with very high spatial resolution and high flux
             to study the composition, structure, electric and magnetic
             properties of complex materials. © 2005 IOP Publishing
             Ltd.},
   Doi = {10.1088/0953-8984/17/16/005},
   Key = {fds249384}
}

@article{fds249386,
   Author = {Fransen, C and Pietralla, N and Tonchev, AP and Ahmed, MW and Chen, J and Feldman, G and Kneissl, U and Li, J and Litvinenko, VN and Perdue, B and Pinayev, IV and Pitz, HH and Prior, R and Sabourov, K and Spraker, M and Tornow, W and Weller, HR and Werner, V and Wu, YK and Yates,
             SW},
   Title = {Parity assignments to strong dipole excitations of Zr-92 and
             Mo-96},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {70},
   Number = {4},
   Pages = {044317},
   Year = {2004},
   Month = {October},
   ISSN = {0556-2813},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000225043100035&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {Parity quantum numbers for dipole-excited states of the
             nuclei 92Zr and 96Mo have been determined from azimuthal
             asymmetries of nuclear resonance fluorescence intensities
             induced with the linearly polarized photon beam of the HIGS
             facility at Duke University. This parity information is
             crucial for an interpretation of the investigated J = 1
             states as two-phonon excitations originating from
             inhomogeneous phonon coupling.},
   Doi = {10.1103/PhysRevC.70.044317},
   Key = {fds249386}
}

@article{fds292652,
   Author = {Feng, J and MacDowell, AA and Duarte, R and Doran, A and Forest, E and Kelez, N and Marcus, M and Munson, D and Padmore, H and Petermann, K and Raoux, S and Robin, D and Scholl, A and Schlueter, R and Schmid, P and Stöhr, J and Wan, W and Wei, DH and Wu, Y},
   Title = {An Aberration Corrected Photoemission Electron Microscope at
             the Advanced Light Source},
   Journal = {AIP Conference Proceedings},
   Volume = {705},
   Pages = {1070-1073},
   Editor = {T.Warwick, J.Arthur and H.PAdmore, J.Stohr},
   Year = {2004},
   Month = {May},
   ISBN = {0735401799},
   ISSN = {0094-243X},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000222089000263&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {© 2004 American Institute of Physics. Design of a new
             aberration corrected Photoemission electron microscope PEEM3
             at the Advanced Light Source is outlined. PEEM3 will be
             installed on an elliptically polarized undulator beamline
             and will be used for the study of complex materials at high
             spatial and spectral resolution. The critical components of
             PEEM3 are the electron mirror aberration corrector and
             aberration-free magnetic beam separator. The models to
             calculate the optical properties of the electron mirror are
             discussed. The goal of the PEEM3 project is to achieve the
             highest possible transmission of the system at resolutions
             comparable to our present PEEM2 system (50 nm) and to enable
             significantly higher resolution, albeit at the sacrifice of
             intensity. We have left open the possibility to add an
             energy filter at a later date, if it becomes necessary
             driven by scientific need to improve the resolution
             further.},
   Doi = {10.1063/1.1757983},
   Key = {fds292652}
}

@article{fds249385,
   Author = {Wu, YK and Robin, DS and Forest, E and Schlueter, R and Anders, S and Feng,
             J and Padmore, H and Wei, DH},
   Title = {Design and analysis of beam separator magnets for third
             generation aberration compensated PEEMs},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {519},
   Number = {1-2},
   Pages = {230-241},
   Year = {2004},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/j.nima.2003.11.160},
   Abstract = {A state of the art X-ray photoemission electron microscope
             (PEEM2) is operational at the Advanced Light Source at a
             resolution of typically 50 nm for a range of chemical and
             magnetic surface studies. A new microscope, PEEM3, is under
             development with an aim of achieving a resolution of 5 nm
             and more than an order of magnitude increase in transmission
             at the nominal resolution of PEEM2. The resolution and flux
             improvement is realized by providing geometric and chromatic
             aberration compensations in the system using an electron
             mirror and a beam separator magnet. The nearly
             aberration-free design of the beam separator is critical to
             the performance of third generation PEEMs. In this paper, we
             present the optics design model, optimal operation
             parameters, analyses of aberration impact, as well as the
             mechanical alignment tolerance for PEEM3 separator
             prototypes. In particular, we emphasize the importance of a
             new semi-analytical approach to design complex charged
             particle optics using the truncated power series algebra.
             Because of its ability to compute high-order aberrations,
             this approach allows systematic and comprehensive analyses
             of any charged particle optics systems with analytical
             electric and magnetic fields. © 2003 Published by Elsevier
             B.V.},
   Doi = {10.1016/j.nima.2003.11.160},
   Key = {fds249385}
}

@article{fds249387,
   Author = {Ahmed, MW and Feldman, G and Litvinenko, VN and Nelson, SO and Norum,
             BE and Perdue, B and Pinayev, IV and Sawatzky, B and Tonchev, AP and Wu, Y and Weller, HR},
   Title = {Background reduction in FEL-generated γ-ray beam
             experiments using giant high-peak power pulses},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {516},
   Number = {2-3},
   Pages = {440-444},
   Year = {2004},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/j.nima.2003.08.166},
   Abstract = {A new method to eliminate beam-uncorrelated background in
             photonuclear experiments has been developed at the High
             Intensity Gamma-Ray Source (HIγS). Background suppression
             of over 3 orders-of-magnitude has been achieved by using a
             gain modulation technique to generate giant high-peak power
             (GHPP) pulses in the OK-4/ Duke storage ring FEL. The time
             structure of these laser pulses was tuned so that their
             duration was ∼100 μs, repeated every 50 ms. The
             associated FEL photons were backscattered from 780 MeV
             electrons to produce linearly polarized 40 MeV γ-rays
             having the same time structure as the FEL pulses. As an
             initial test of the technique, a nearly background-free
             measurement of the analyzing power in the Compton scattering
             reaction 16O(γ→,γ)16O was performed. © 2003 Elsevier
             B.V. All rights reserved.},
   Doi = {10.1016/j.nima.2003.08.166},
   Key = {fds249387}
}

@article{fds249388,
   Author = {Wu, YK and Forest, E and Robin, DS},
   Title = {Explicit symplectic integrator for s-dependent static
             magnetic field},
   Journal = {Physical Review E},
   Volume = {68},
   Number = {68},
   Pages = {046502},
   Publisher = {The American Physical Society},
   Year = {2003},
   Month = {October},
   ISSN = {1063-651X},
   url = {http://link.aps.org/abstract/PRE/v68/e046502},
   Abstract = {This paper reports our recent work on explicit symplectic
             integration techniques for the charged particle motion in an
             s-dependent static magnetic field. Using the extended phase
             space, symplectic integrators can be developed for
             Hamiltonians with or without the paraxial approximation
             using either the space or time as an independent variable.
             This work extends the successful element-by-element tracking
             method for studying single-particle nonlinear dynamics to a
             set of s-dependent magnetic elements. Important applications
             of this work include the studies of the charged particle
             dynamics in a storage ring with various insertion devices,
             superconducting magnets, large aperture magnets with
             significant fringe fields, and solenoid magnets in the
             interaction region. Consequently, this work is expected to
             make an impact on design and optimal operation of existing
             and future light source rings and high energy physics
             accelerators.},
   Key = {fds249388}
}

@article{fds17523,
   Author = {M.W. Ahmeda and G. Feldmana and b, V.N. Litvinenkoc and S.O. Nelsona and B.E. Norumd and B. Perduea and I.V. Pinayevc and B. Sawatzkyd and A.P.
             Toncheva, Y. Wu  and H.R. Weller},
   Title = {Background reduction in FEL-generated g-ray beam experiments
             using giant high-peakpower pulses},
   Journal = {Nuclear Instruments and Methods in Physics Research
             A},
   Number = {516},
   Pages = {440-444},
   Year = {2003},
   Month = {August},
   Abstract = {A new method to eliminate beam-uncorrelated background in
             photonuclear experiments has been developed at the High
             Intensity Gamma-Ray Source (HIgS). Background suppression of
             over 3 orders-of-magnitude has been achieved by using a gain
             modulation technique to generate giant high-peakpower (GHPP)
             pulses in the OK-4/ Duke storage ring FEL. The time
             structure of these laser pulses was tuned so that their
             duration was B100 ms; repeated every 50 ms: The associated
             FEL photons were backscattered from 780 MeV electrons to
             produce linearly polarized 40 MeV g-rays having the same
             time structure as the FEL pulses. As an initial test of the
             technique, a nearly background-free measurement of the
             analyzing power in the Compton scattering reaction 16Oð~g;
             gÞ16O was performed. r 2003 Elsevier B.V. All rights
             reserved.},
   Key = {fds17523}
}

@article{fds249294,
   Author = {Wan, W and Nishimura, H and Robin, D and Steier, C and Wu, Y and Forest,
             E},
   Title = {ID modeling at the ALS},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2249-2251},
   Year = {2003},
   Month = {Winter},
   Abstract = {At the Advanced Light Source there are several projects
             being proposed that will require high field insertion
             devices. It is important that these devices do not
             significantly impact the performance of the machine. In
             particular they should not degrade the beam lifetime or
             injection efficiency. It is known that high field devices
             with large field roll off can impact the beam lifetime. It
             is therefore important to model the effect of the insertion
             devices including both transverse and longitudinal field
             roll off. In this paper we present the result of tracking
             studies using an explicit symplectic integrator with both
             transverse and longitudinal field roll off. The simulations
             show where sufficiently large field roll off will impact the
             beam lifetime.},
   Key = {fds249294}
}

@article{fds249295,
   Author = {Wu, YK and Li, J and Wang, P and Litvinenko, V},
   Title = {BPM and orbit correction systems at the Duke storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2479-2481},
   Year = {2003},
   Month = {Winter},
   Abstract = {Stable and reliable storage ring operation critically
             depends on the orbit stability. At Duke, an orbit stability
             program is well under way to achieve the high level of orbit
             performance necessary for reliable free electron laser (FEL)
             and gamma-ray operation. Progress has been made to reduce
             the current dependency of BPM readings via choice of cables
             and band-pass filters. Beam based alignment has been carried
             out to accurately determine the locations of quadrupole
             centers. A global orbit correction system and a slow orbit
             feedback system have been developed. Integrated with
             operation, these systems have demonstrated the ability to
             significantly improve the overall storage ring
             performance.},
   Key = {fds249295}
}

@article{fds249296,
   Author = {Steier, C and Forest, E and Nadolski, L and Nishimura, H and Robin, D and Wan, W and Wu, Y and Zholents, A},
   Title = {Accelerator physics challenges of the fs-slicing upgrade at
             the ALS},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {397-399},
   Year = {2003},
   Month = {Winter},
   Abstract = {The goal of the Femtoslicing project at the ALS is to
             provide 100-200 fs long pulses of soft and hard x-rays with
             moderate flux and with a repetion rate of 10-40 kHz for
             experiments concerning ultrafast dynamics in solid state
             physics, chemistry and biology. The femtoslicing principle
             employs a femtosecond laser beam to interact resonantly
             (inverse FEL interaction) with the electron beam in the ALS.
             The induced energy spread over the femtosecond duration is
             converted to a transverse displacement by exploiting the
             dispersion of the storage ring. The displaced femtosecond
             electron pulse then radiates and produces femtosecond
             synchrotron radiation. To achieve the necessary spatial
             separation of the energy modulated slice from the rest of
             the bunch, a sizeable local vertical dispersion bump in the
             undulator used as radiator is required. This presents
             challenges in terms of the nonlinear dynamics and control of
             the vertical emittance.},
   Key = {fds249296}
}

@article{fds249297,
   Author = {Mikhailov, S and Litvinenko, V and Busch, M and Emamian, M and Hartman,
             S and Pinayev, I and Popov, V and Swift, G and Wallace, P and Wu, Y and Gavrilov, N and Matveev, Y and Shvedov, D and Vinokurov, N and Vobly,
             P},
   Title = {Status of the booster synchrotron for Duke FEL storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2273-2275},
   Year = {2003},
   Month = {Winter},
   Abstract = {In this paper we present current status of the Booster
             Synchrotron for the Duke FEL storage ring. The Booster which
             is recently under design, fabrication and construction, will
             provide full energy injection into the storage ring at
             energy from 0.3 to 1.2 GeV. The Duke storage ring FEL (SR
             FEL) operates in lasing mode with 193-700 nm wavelength
             range. The geometry of the Duke SR FEL provides for
             interacting head-on collision of e-beam and FEL photons.
             This mode of operation is used to generate intense beams of
             γ-rays from 2 MeV to about 200 MeV (currently from 2 MeV to
             58 MeV). Generation of γ-rays with energy exceeding 20 MeV
             causes the loss of electrons, which will be replaced by
             injection from the Booster operating in a top-off mode. The
             paper presents design and status for elements of magnetic
             system and vacuum system, as well as design and parameters
             of fast extraction kicker with 11 nS pulse duration. All
             these element are designed and will be fabricated by Budker
             Institute of Nuclear Physics, Novosibirsk,
             Russia.},
   Key = {fds249297}
}

@article{fds249298,
   Author = {Wu, YK and Popov, VG and Hartman, S and Pinayev, I and Mikhailov, SF and Morcombe, P and Oakeley, O and Wallace, P and Wang, P and Litvinenko,
             V},
   Title = {Improving power supply performance for the Duke storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2},
   Pages = {752-754},
   Year = {2003},
   Month = {Winter},
   Abstract = {As part of the recent Duke storage ring hardware upgrade
             (2001-2002), a power supply improvement program was put in
             place to bring all major DC supplies to their
             specifications. In carrying out this program, power supplies
             have been modified, tuned, and thoroughly tested. In its
             actual operation configuration, each power supply was
             subject to extensive testing to determine its DC stability,
             reproducibility and linearity, AC ripple and noise, and
             ramping performance. As a result, all major DC supplies have
             been improved to meet most important performance
             specifications for 1 GeV operation.},
   Key = {fds249298}
}

@article{fds249299,
   Author = {Wu, YK and Li, J and Mikhailov, SF and Litvinenko,
             V},
   Title = {Nonlinear dynamics in the Duke storage ring with FEL
             wigglers},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {391-393},
   Year = {2003},
   Month = {Winter},
   Abstract = {Single particle dynamics in the storage ring can be
             significantly influenced by strong nonlinearities from long
             and strong-field insertion devices. This paper reports our
             preliminary results on the dynamics impact of the 24 m long
             OK5 FEL in the Duke ring. Initial studies are performed
             using an intermediate lattice with two OK5 wigglers. The
             dynamic aperture is computed using a recently developed
             symplectic wiggler integrator and the frequency map
             technique, NAFF. We have observed significant dynamic
             aperture reduction due to OK5 wigglers at lower beam
             energies. We also report our preliminary findings on the
             means to improve beam dynamics with wigglers.},
   Key = {fds249299}
}

@article{fds249300,
   Author = {Wu, YK and Hartman, S and Mikhailov, SF},
   Title = {A physics based control system for the Duke storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2482-2484},
   Year = {2003},
   Month = {Fall},
   Abstract = {At the Duke FEL Lab, we have developed a new storage ring
             control system in terms of the physics quantities of the
             accelerator. Instead of controlling power supply currents in
             Amperes, this system controls the effective focusing of
             magnets. By directly controlling the physics quantities,
             this control system allows tighter integration of the
             physics model based high level controls with the EPICS based
             low-level controls. EPICS events have been extensively used
             to provide time synchronization during the energy and
             lattice ramping. This new control system also facilitates
             the implementation of multiple functions on shared control
             channels. As a result, the physics based control system
             simplifies many complex control tasks, improves the beam
             stability during ramping, and facilitates machine studies.
             With better understanding of the accelerator, it is possible
             to fine tune this control system to present users with a
             virtual accelerator whose operation is independent of the
             ring energy.},
   Key = {fds249300}
}

@article{fds249301,
   Author = {Li, J and Wu, YK and Hartman, S},
   Title = {Power supply performance monitoring and analysis using
             operation data},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2270-2272},
   Booktitle = {Proceedings of PAC2003},
   Year = {2003},
   Month = {Winter},
   Abstract = {Magnet power supplies are critical components of a storage
             ring. The performance of power supplies directly impacts the
             stability and reliability of the storage ring operation.
             There are several type of DC power supplies in Duke FEL
             storage ring. The performance data of power supplies can be
             collected in a non-interruptive manner by an EPICS archiver
             or by a MATLAB program. MATLAB based tools have been
             developed to analyze the power supply data collected during
             the operation. Careful evaluation of data allows us to
             identify a power supply with degraded performance and
             provide a reference to perform preventive
             maintenance.},
   Key = {fds249301}
}

@article{fds249389,
   Author = {Feng, J and Padmore, H and Wei, DH and Anders, S and Wu, Y and Scholl, A and Robin, D},
   Title = {Modeling the acceleration field and objective lens for an
             aberration corrected photoemission electron
             microscope},
   Journal = {Review of Scientific Instruments},
   Volume = {73},
   Number = {3},
   Pages = {1514-1517},
   Year = {2002},
   Month = {December},
   ISSN = {0034-6748},
   url = {http://dx.doi.org/10.1063/1.1423631},
   Abstract = {The modeling of the optical properties of the acceleration
             field and objective lens of a photoemission electron
             microscope (PEEM) is presented. Theory to calculate the
             aberrations of the extraction field was derived, and
             extended to include relativistic effects. An analysis of the
             microscope's electron optical performance and aberrations
             has been performed using an analytical model as well as a
             ray tracing method. Ray tracing has the flexibility needed
             for the assessment of aberrations where the geometry is too
             complex for analytical methods. This work shows that in the
             case of a simple PEEM front end of the acceleration gap and
             objective lens, the all orders ray tracing and full
             analytical treatments agree to very high precision. This
             allows us now to use the ray tracing method in situations
             where analytical methods are difficult, such as an
             aberration compensating electron mirror.},
   Doi = {10.1063/1.1423631},
   Key = {fds249389}
}

@article{fds249367,
   Author = {Steier, C and Robin, D and Nadolski, L and Decking, W and Wu, Y and Laskar,
             J},
   Title = {Measuring and optimizing the momentum aperture in a particle
             accelerator},
   Journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter
             Physics},
   Volume = {65},
   Number = {5},
   Pages = {056506/1-056506/17},
   Year = {2002},
   ISSN = {1539-3755},
   url = {http://dx.doi.org/10.1103/PhysRevE.65.056506},
   Abstract = {Particle motion in storage rings is confined by various
             aperture limits, the size of which restricts the performance
             of the ring in terms of injection efficiency, lifetime, etc.
             Intrabeam scattering makes particles sweep a large portion
             of the phase space, where their motion may eventually be
             resonantly or chaotically excited to large amplitudes
             leading to collision with the vacuum chamber. We report here
             the studies performed at the Advanced Light Source (ALS) on
             the on- and off-momentum particle motion that provides a
             good understanding of these limitations. Using off-momentum
             simulations and experiments together with frequency map
             analysis, we could precisely correlate beam loss areas with
             resonance locations. The very good agreement between
             simulations and experiments allowed us to provide guidance
             for avoiding these dangerous areas. This analysis results in
             predictive improvements of the momentum aperture, which
             actually led to a lifetime increase of 25% at the ALS for
             very high bunch charge. © 2002 The American Physical
             Society.},
   Doi = {10.1103/PhysRevE.65.056506},
   Key = {fds249367}
}

@article{fds249390,
   Author = {Wu, Y and Nishimura, H and Robin, DS and Zholents, AA and Forest,
             E},
   Title = {Mini-beta lattice for the femto-second X-ray source at the
             Advanced Light Source},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {481},
   Number = {1-3},
   Pages = {675-681},
   Year = {2002},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01353-5},
   Abstract = {After generating the first femto-second X-ray pulses at the
             Advanced Light Source (ALS), it becomes critical to improve
             the flux of this femto-second source for user experiments. A
             narrow-gap in-vacuum undulator has been proposed to be
             installed in one of the ALS straight sections. To realize
             the optimal performance of this undulator, a straight
             section lattice with a mini vertical beta function has been
             designed. Separation of electrons has been achieved by
             generating a sizable vertical dispersion via a local
             dispersion bump and a closed orbit bump. Particle tracking
             study shows that the modified ALS lattice for the
             femto-second X-ray source has an adequate dynamic aperture.
             © 2002 Published by Elsevier Science B.V.},
   Doi = {10.1016/S0168-9002(01)01353-5},
   Key = {fds249390}
}

@article{fds304633,
   Author = {Feng, J and Padmore, H and Wei, DH and Anders, S and Wu, Y and Scholl, A and Robin, D},
   Title = {Modeling the acceleration field and objective lens for an
             aberration corrected photoemission electron
             microscope},
   Journal = {Review of Scientific Instruments},
   Volume = {73},
   Number = {3 II},
   Pages = {1514-},
   Year = {2002},
   ISSN = {0034-6748},
   url = {http://dx.doi.org/10.1063/1.1423631},
   Doi = {10.1063/1.1423631},
   Key = {fds304633}
}

@article{fds4263,
   Author = {C. Steier and D. Atkinson and J. Byrd and J. Corlett and H. Nishimura and D. Robin and S. de Santis},
   Title = {INTRA-BEAM SCATTERING AND MINIMUM ACHIEVABLE},
   Pages = {2938-2940},
   Booktitle = {INTRA-BEAM SCATTERING AND MINIMUM ACHIEVABLE},
   Year = {2001},
   Month = {June},
   Abstract = {Intra-beam scattering (IBS) potentially limits the mini-mum
             emittance of low-energy storage rings, and this ef-fect
             strongly influences the choice of energy of damping rings
             for linear colliders. The Advanced Light Source (ALS) is a
             third-generation synchrotron light source oper-ating with
             high-intensity, low-emittance beams at energies up to 2 GeV.
             It can operate with an emittance coupling of below 1%. We
             present measurements of the beam growth in three dimensions
             as a function of current, for normal-ized natural horizontal
             emittances of approximately 1 - 10 mm-mrad at energies of
             0.7 - 1.5 GeV, values compara-ble to the parameters in an
             NLC damping ring [1]. Using a dedicated diagnostic beamline
             with an x-ray scintillator imaging system, measurements of
             the transverse beamsize are made, simultaneously with bunch
             length measurements using an optical streak camera. The
             bunch volume growth as a function of bunch current is
             compared with theoretical estimates, for a parameter space
             of IBS, where very little experimental data exists so
             far.},
   Key = {fds4263}
}

@article{fds17524,
   Author = {J. H. Kelley and B. T. Crowley and V. N. Litvinenko and S.H. Park and I.V. Pinayev and E. C. Schreiber and W. Tornow and Y. Wu and H. R.
             Weller},
   Title = {High-Intensity y-ray Source},
   Journal = {AIP Conference Proceedings},
   Volume = {576},
   Pages = {659},
   Publisher = {American Institute of Physics},
   Year = {2001},
   Abstract = {A mono-energetic tunable source of 100% linearly polarized y
             rays has been developed at the Duke Free- Electron Laser
             Laboratory in conjunction with Triangle Universities Nuclear
             Laboratory. The OK-4 PEL is coupled to a 1-GeV electron
             storage ring and generates intense beams of visible or UV
             photons. In y-ray production mode, the OK-4 photons Compton
             scatter from high-energy electrons inside the optical cavity
             leading to backscattered y rays. The strong correlation
             between scattering angle and y-ray energy permits a
             selection of the energy spread of the y-ray beam that
             depends on a simple geometrical aperture located along the
             optical axis. Results obtained/(design parameters) indicate
             yray beams with energies of 2.2-587(2.0-175) MeV, AE/E<1.0%
             and total fluxes greater than 107/(1010) y
             rays/s.},
   Key = {fds17524}
}

@article{fds249282,
   Author = {Wu, Y and Forest, E and Robin, DS and Nishimura, H and Wolski, A and Litvinenko, VN},
   Title = {Symplectic models for general insertion devices},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {459-461},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {A variety of insertion devices (IDs), wigglers and
             undulators, linearly or elliptically polarized, are widely
             used as high brightness radiation sources at the modern
             light source rings. Long and high-field wigglers have also
             been proposed as the main source of radiation damping at
             next generation damping rings. As a result, it becomes
             increasingly important to understand the impact of IDs on
             the charged particle dynamics in the storage ring. In this
             paper, we report our recent development of a general
             explicit symplectic model for IDs with the paraxial ray
             approximation. High-order explicit symplectic integrators
             are developed to study real-world insertion devices with a
             number of wiggler harmonics and arbitrary
             polarizations.},
   Key = {fds249282}
}

@article{fds249283,
   Author = {Steier, C and Atkinson, D and Byrd, J and Corlett, J and Nishimura, H and Robin, D and Santis, SD and Wolski, A and Wu, Y and Bane, K and Raubenheimer, T and Ross, M and Sheppard, J and Smith,
             T},
   Title = {Intra-beam scattering and minimum achievable emittance in
             the advanced light source},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2938-2940},
   Year = {2001},
   Abstract = {Intra-beam scattering (IBS) potentially limits the minimum
             emittance of low-energy storage rings, and this effect
             strongly influences the choice of energy of damping rings
             for linear colliders. The Advanced Light Source (ALS) is a
             third-generation synchrotron light source operating with
             high-intensity, low-emittance beams at energies up to 2 GeV.
             It can operate with an emittance coupling of below 1%. We
             present measurements of the beam growth in three dimensions
             as a function of current, for normalized natural horizontal
             emittances of approximately 1 - 10 mm-mrad at energies of
             0.7 - 1.5 GeV, values comparable to the parameters in an NLC
             damping ring. Using a dedicated diagnostic beamline with an
             x-ray scintillator imaging system, measurements of the
             transverse beamsize are made, simultaneously with bunch
             length measurements using an optical streak camera. The
             bunch volume growth as a function of bunch current is
             compared with theoretical estimates, for a parameter space
             of IBS, where very little experimental data exists so
             far.},
   Key = {fds249283}
}

@article{fds249284,
   Author = {Steier, C and Biocca, A and Domning, E and Jacobson, S and Portmann, G and Wu, Y},
   Title = {Design of a fast global orbit feedback system for the
             Advanced Light Source},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2},
   Pages = {1252-1254},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {The fast stability of the closed orbit of the electron beam
             at the Advanced Light Source (ALS) at Lawrence Berkeley
             National Laboratory fulfills user requirements so far
             without any fast active correction system. In the range
             between 0.1 and 500 Hz the integrated rms closed orbit
             motion is significantly below one tenth of one sigma
             beamsizes. For the future there is some user demand to
             improve this stability further. Moreover, the expansion of
             the capabilities of the ALS creates new sources of closed
             orbit noise. Therefore the design of a fast, global orbit
             feedback system has been started in conjunction with a
             general upgrade of the ALS control system. It will initially
             operate with an update rate of 500 Hz - 1 kHz, will include
             24 beam position monitors and corrector magnets in each
             plane and will use standard computer and networking
             architecture. The system design, measurements of transfer
             functions and tests with small prototype systems will be
             presented.},
   Key = {fds249284}
}

@article{fds249285,
   Author = {Shevchenko, OA and Litvinenko, VN and Mikhailov, SM and Vinokurov,
             NA and Gavrilov, NG and Vobly, PD and Wu, Y},
   Title = {The VUV/UV OK-5 Duke storage ring FEL with variable
             polarization},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2833-2835},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {We discuss the design and expected performance of the OK-5
             FEL, which will replace in 2002 the OK-4 FEL operating now
             at the Duke storage ring. The OK-5 FEL is the first
             distributed optical klystron with variable polarization. The
             design of wigglers and matching sections is flexible for
             providing optimal conditions for variety of operation modes.
             In this paper we present calculations of the main OK-5 FEL
             parameters such as its tuning range, gain and lasing power.
             Based on our calculations we present the predictions for the
             OK-5 gamma-ray source. We conclude with description of the
             current status of the OK-5 FEL and plans for its
             installation.},
   Key = {fds249285}
}

@article{fds249286,
   Author = {Steier, C and Robin, D and Wu, Y and Decking, W and Laskar, J and Nadolski,
             L},
   Title = {Understanding the dynamic momentum aperture of the advanced
             light source},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {434-436},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {The lifetime of a light source with small emittance like the
             Advanced Light Source (ALS) is usually limited by the
             momentum acceptance of the ring. Large momentum acceptances
             are reached by providing enough RF voltage and by avoiding a
             degradation of the dynamic momentum aperture. At the ALS the
             size of the momentum acceptance depends strongly on the
             transverse dynamics. It is very sensitive to machine
             conditions such as the tunes and chromaticities since
             depending on those conditions the Touschek scattered
             particles explore different resonance regions in the phase
             space. In this paper we show that by using a single-turn
             'pinger' magnet together with turn-by-turn beam position
             monitors (BPM) one can identify the cause of a reduction in
             momentum acceptance and take steps to improve the
             acceptance.},
   Key = {fds249286}
}

@article{fds249287,
   Author = {Wolski, A and Wu, Y},
   Title = {Effects of damping wigglers on beam dynamics in the NLC
             damping rings},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {5},
   Pages = {3798-3800},
   Booktitle = {EFFECTS OF DAMPING WIGGLERS ON BEAM DYNAMICS Proceedings of
             the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {To achieve the required damping time in the main damping
             rings for the Next Linear Collider (NLC), a wiggler will be
             required in each ring with integrated squared field strength
             up to 110 T2m. There are concerns that nonlinear components
             of the wiggler field will damage the dynamic aperture of the
             ring, leading to poor injection efficiency. Severe effects
             from an insertion device have been observed and corrected in
             SPEAR 2. In this paper, we describe a model that we have
             developed to study the effects of the damping wiggler,
             compare the predictions of the model with actual experience
             in the case of the SPEAR 2 wiggler, and consider the
             predicted effects of current damping wiggler design on the
             NLC main damping rings.},
   Key = {fds249287}
}

@article{fds249288,
   Author = {Hartman, S and Litvinenko, VN and Swift, G and Pinayev, I and Wu,
             Y},
   Title = {Control system design and upgrade considerations for the
             Duke Free Electron Laser Laboratory},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2},
   Pages = {785-787},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicag},
   Year = {2001},
   Abstract = {The Duke Free Electron Laser Laboratory currently operates
             two FELs: the OK-4/Duke Storage Ring FEL, and the Mark III
             IR FEL. Both of these systems were among the early adopters
             of the Experimental Physics and Industrial Control System
             (EPICS). The Mark III EPICS control system was completed and
             operational in September, 1993. The Duke Storage Ring was
             commissioned in November of 1994 using EPICS. These control
             systems have proven to be very robust with high reliability
             over the intervening years. An overview of these current
             control systems and an upgrade strategy will be
             presented.},
   Key = {fds249288}
}

@article{fds249289,
   Author = {Mikhailov, SF and Litvinenko, VN and Wu, Y},
   Title = {Low emittance lattices for the Duke FEL Storage
             Ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {5},
   Pages = {3528-3530},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {In this paper we present two options for a new lattice of
             the I GeV Duke FEL Storage Ring reducing horizontal beam
             emittance from existing 18 nm*rad to 1.4 nm*rad and 0.9
             nm*rad respectively. One of proposed lattices reuses
             existing magnetic elements, another is based on completely
             new design. The use of combined function magnets with
             dipole, quadrupole and sextupole components allows us to
             keep the ring compact and fit it into existing footprint. 2D
             and 3D field simulations for such a magnet showed good
             quality of magnetic field. Preliminary results for dynamic
             aperture simulations are also presented. We also discuss the
             choice of lattice cell and tune advances and the concept of
             local compensation of nonlinear aberrations.},
   Key = {fds249289}
}

@article{fds249290,
   Author = {Barry, W and Biocca, A and Byrd, JM and Byrne, W and Kwiatkowski, S and Martin, MC and McKinney, WR and Nishimura, H and Sannibale, F and Steier, C and Rex, K and Robin, D and Stover, G and Thur, W and Wu,
             Y},
   Title = {A dedicated infrared synchrotron radiation source at the
             ALS},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2623-2625},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {We present ideas for a storage ring dedicated to and
             optimized for the production of synchrotron radiation over
             the infrared wavelength range from 1-1000 μm. The site for
             the 66 m circumference ring is atop the existing ALS booster
             synchrotron shielding. This area provides enough floor space
             for both the ring and beamlines, and hutches. We plan to
             operate the ring in two modes: as a conventional light
             source and as a superradiant source in the far-IR. In the
             conventional mode, our design allows greater transmission of
             light at longer wavelengths in the far-infrared than typical
             light sources and significantly improves beam stability. In
             the superradiant mode, we hope to achieve coherent emission
             of synchrotron radiation over the 200-1000 μm wavelength
             range by shortening the bunches at very low bunch
             current.},
   Key = {fds249290}
}

@article{fds249291,
   Author = {Litvinenko, VN and Shevchenko, OA and Mikhailov, SF and Wu,
             Y},
   Title = {Project for generation of femtosecond X-ray beams from the
             Duke storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2614-2616},
   Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
             Chicago},
   Year = {2001},
   Abstract = {We propose to develop a CW X-ray femtosecond (fsec) source
             at 1.2 GeV Duke storage ring with the X-ray energy tuneable
             from 1.4 KeV to 75 keV, the average flux from 1012 to 1013
             ph/sec, and the average spectral brightness up to 0.51015
             ph/sec/mm2/mrad2/0.1%BW. A novel RF system with strong
             longitudinal focusing will compress and to sustain the
             electron bunches circulating in the ring to a RMS duration
             from 15 to 85 fsec. The CW fsec electron bunches will
             generate the Compton hard-X-ray beams and the photon beams
             from the existing light sources ranging form IR to VUV.
             Beams of all colours will be synchronised by the e-beam
             without jitter, making this configuration perfectly suites
             for pump-probe experiments. The proposed approach promises
             to outperform the popular "slicing technique" by at least
             three orders of magnitude. Duke's approach can be
             implemented at existing light source facilities at modest
             cost.},
   Key = {fds249291}
}

@article{fds249292,
   Author = {Pinayev, IV and Litvinenko, VN and Park, SH and Wu, Y and Emamian, M and Hower, N and Patterson, J and Swift, G},
   Title = {Giant high-peak power pulses in the UV OK-4/Duke storage
             ring FEL using the gain modulator},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {222-228},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01572-8},
   Abstract = {We use the gain modulation technique to generate giant
             pulses in the OK-4/Duke storage ring FEL for applications
             requiring high peak power. This technique provides the
             increase of the peak power by several orders of magnitude.
             It is also very reliable, predictable and reproducible. The
             design, the parameters and the gain modulator performance
             are described. Comparison of expected and measured pulse
             forms is presented. Application of gain modulator for future
             harmonic generation experiments is also discussed. © 2001
             Elsevier Science B.V. All rights reserved.},
   Doi = {10.1016/S0168-9002(01)01572-8},
   Key = {fds249292}
}

@article{fds249369,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu,
             Y},
   Title = {Operation of the OK-4/Duke storage ring FEL below 200
             nm},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {195-204},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01559-5},
   Abstract = {For a number of years the wavelength of 200 nm was a
             psychological barrier for FEL oscillators. The progress
             towards short wavelength was marginal since the OK-4/VEPP-3
             storage ring FEL lased at 240 nm in 1988. After 10 years, in
             1998, the OK-4/Duke FEL and the NIJI-IV FEL group moved the
             limit to 217 and 212 nm, respectively. Improvements of the
             OK-4/Duke storage ring FEL gain above 10% and the use of
             custom manufactured mirror coatings brought the success in
             August 1999. The OK-4 FEL lased in the range from 193.7 to
             209.8 nm using electron energies from 500 to 800 MeV. In
             this paper, we present the description of the OK-4/Duke FEL
             up-grades and the lasing results below 200 nm obtained in
             August and October of 1999. © 2001 Elsevier Science B.V.
             All rights reserved.},
   Doi = {10.1016/S0168-9002(01)01559-5},
   Key = {fds249369}
}

@article{fds249370,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu,
             Y},
   Title = {Time structure of the OK-4/Duke storage ring
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {240-246},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01569-8},
   Abstract = {In this paper, we present results of experimental and
             theoretical studies of macro- and micro-temporal of dynamics
             of the OK-4/Duke storage ring FEL (SR FEL) and electron
             beams. The experimental part of these studies utilized the
             Hamamatsu C5680 dual-sweep streak-camera with 1.2ps
             resolution. We use both numerical and analytical tools for
             theoretical analysis of the FEL and e-beam distributions
             without any pre-imposed limitations. Our experimental
             results are in good agreement with the theoretical
             predictions. © 2001 Elsevier Science B.V. All rights
             reserved.},
   Doi = {10.1016/S0168-9002(01)01569-8},
   Key = {fds249370}
}

@article{fds249383,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu, Y and Lumpkin, A and Yang, B},
   Title = {Fourier limited micro-pulses in the OK-4/Duke storage ring
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {234-239},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01570-4},
   Abstract = {The Super-modes are Fourier limited FEL micro-pulses
             predicted by Dattoli and Renieri in 1980. The OK-4 FEL at
             Duke, operating in the wavelength range from 193.7nm to
             730nm, was the first to observe the Super-modes in a storage
             ring FEL in 1996. Since 1996, the up-graded diagnostics and
             improved control of the RF frequency allowed generation of
             Super-modes on a regular basis and systematic study of them.
             The Gaussian FEL micro-pulses with 1.3ps RMS duration and
             Fourier limited RMS linewidth were generated in 1998-1999.
             In this paper we present the results of our studies and the
             comparison with theoretical predictions. We also present
             practical criteria for operating SR FELs with Super-modes.
             © 2001 Elsevier Science B.V. All rights
             reserved.},
   Doi = {10.1016/S0168-9002(01)01570-4},
   Key = {fds249383}
}

@article{fds249391,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu,
             Y},
   Title = {Power limitations in the OK-4/Duke storage ring
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {65-73},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01536-4},
   Abstract = {In this paper, we present results of our experimental and
             theoretical studies of average power in the OK-4/Duke
             storage ring FEL. Our theoretical studies are based on the
             3D FEL macro-particle model, which includes the local
             interactions, diffusion, radiation damping and spontaneous
             radiation. The OK-4/Duke storage ring FEL is operational
             since 1996 and demonstrated lasing in a wavelength range
             from 193.7 to 730nm using electron beam energies from 220 to
             800MeV. It operated in both CW and giant pulse modes. During
             this period of time we collected substantial amounts of data
             regarding the FEL power and electron beam dynamics. We
             compare selected results on CW lasing with our theoretical
             predictions based on the rigorous numerical model. We also
             discuss a number of simplified scaling laws for the FEL gain
             and power as functions of electron beam energy and current,
             as well as, the cavity losses. © 2001 Elsevier Science B.V.
             All rights reserved.},
   Doi = {10.1016/S0168-9002(01)01536-4},
   Key = {fds249391}
}

@article{fds249392,
   Author = {Wu, Y and Litvinenko, VN and Mikhailov, SF and Shevchenko, OA and Vinokurov, NA and Gavrilov, NG and Shaftan, TV and Kairan,
             DA},
   Title = {Lattice modification and nonlinear dynamics for elliptically
             polarized VUV OK-5 FEL source at Duke storage
             ring},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {253-259},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01567-4},
   Abstract = {The Duke storage ring is a light source ring optimized for
             driving the Free Electron Lasers (FELs). To take advantage
             of the high brightness of the electron beam in the storage
             ring, a next generation FEL source - an elliptically
             polarized OK-5 FEL system, has been designed to match the
             electron beam quality of the Duke storage ring. In this
             paper, we present the storage ring lattice modifications
             which are necessary to accommodate the 24 m long OK-5 FEL.
             Because of its length and strong nonlinear focusing, the
             OK-5 FEL is expected to have a significant impact on the
             electron beam dynamics. We also present the preliminary
             results on the dynamic aperture calculation for the OK-5 FEL
             operated in different modes. © 2001 Elsevier Science B.V.
             All rights reserved.},
   Doi = {10.1016/S0168-9002(01)01567-4},
   Key = {fds249392}
}

@article{fds249393,
   Author = {Litvinenko, VN and Mikhailov, SF and Shevchenko, OA and Vinokurov,
             NA and Gavrilov, NG and Kulipanov, GN and Shaftan, TV and Vobly, PD and Wu,
             Y},
   Title = {The OK-5/Duke storage ring VUV FEL with variable
             polarization},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {407-416},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01548-0},
   Abstract = {The OK-5/Duke storage ring free electron laser (FEL) project
             was started in 1998. Presently, the components of the OK-5
             FEL and the new South straight section are in the final
             stage of manufacturing. This paper describes the design and
             the main features of the OK-5/Duke storage ring FEL. The
             basic concepts and main compromises made in the design
             process are presented. Plans for the OK-5 FEL commissioning
             are discussed. © 2001 Elsevier Science B.V. All rights
             reserved.},
   Doi = {10.1016/S0168-9002(01)01548-0},
   Key = {fds249393}
}

@article{fds249394,
   Author = {Mikhailov, SF and Litvinenko, VN and Wu, Y},
   Title = {Low emittance lattice for the Duke storage ring soft X-ray
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {475},
   Number = {1-3},
   Pages = {417-424},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01636-9},
   Abstract = {In this paper, we present a possible lattice for the Duke
             storage ring with horizontal emittance of 1.4nm rad at an
             energy of 1 GeV. The new lattice was constrained to fit the
             layout of the existing storage ring and to re-use existing
             magnets. Within these constrains, the improvement of the
             emittance (from current 18nm rad) is possible due to the use
             in the arcs of combined function bending magnets with strong
             dipole, quadrupole and sextuple fields. We present the
             results of 2D and 3D simulations of magnetic fields for
             these magnets. We discuss the choice of the arc's lattice
             cell and the per-cell tune advance. The lattice is based on
             the concept of local compensation of the non-linear
             geometrical aberrations. Preliminary studies of the dynamic
             aperture for this lattice are very encouraging. We briefly
             discuss the possibility further emittance reduction using
             new magnets for the arcs. © 2001 Published by Elsever
             Science B.V.},
   Doi = {10.1016/S0168-9002(01)01636-9},
   Key = {fds249394}
}

@article{fds249395,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu,
             Y},
   Title = {Performance of the OK-4/Duke storage ring
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {470},
   Number = {1-2},
   Pages = {66-75},
   Year = {2001},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(01)01025-7},
   Abstract = {In this paper, we report measured parameters of the OK-4 FEL
             driven by the Duke storage ring. The OK-4 FEL was being
             operated continuously for 2 yr in the broad wavelength range
             for user applications utilising spontaneous and coherent XUV
             and UV radiation as well as Compton back-scattered γ-rays
             in the range of 2-58 MeV. During this time, the OK-4 FEL
             lased in the range from 193.7 to about 730 nm using five
             sets of mirrors and electron beam energies from 240 to 800
             MeV. Our predictions for the OK-4 FEL are compared with
             measured performance, both in the CW and in the giant pulse
             mode. We discuss our future plans for the OK-4 FEL operation
             as well as the construction and commissioning of the OK-5
             FEL with helical wigglers. © 2001 Elsevier Science B.V. All
             rights reserved.},
   Doi = {10.1016/S0168-9002(01)01025-7},
   Key = {fds249395}
}

@article{fds292660,
   Author = {Schreiber, EC and Canon, RS and Crowley, BT and Howell, CR and Kelley,
             JH and Litvinenko, VN and Nelson, SO and Park, SH and Pinayev, IV and Prior, RM and Sabourov, K and Spraker, M and Tornow, W and Wu, Y and Wulf,
             EA and Weller, HR},
   Title = {First measurement of the near-threshold H-2((gamma)over-right-arrow,n)p
             analyzing power using a free-electron laser based gamma-ray
             source},
   Journal = {Physical Review C - Nuclear Physics},
   Volume = {61},
   Number = {6},
   Year = {2000},
   Month = {June},
   ISSN = {0556-2813},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000087575000005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Doi = {10.1103/PhysRevC.61.061604},
   Key = {fds292660}
}

@article{fds191709,
   Author = {Y. Wu and H. Nishimura and D. S. Robin and A. A. Zholents and E.
             Forest},
   Title = {Mini-Beta Lattice for the Femto-Second X-Ray Source at the
             Advanced Light Source},
   Journal = {Proceedings of Seventh European Particle Accelerator
             Conference (EPAC 2000)},
   Pages = {1098-1100},
   Year = {2000},
   Abstract = {After generating the first femto-second X-ray pulses at the
             Advanced Light Source (ALS), it becomes critical to improve
             the flux of this femto-second source for user experiments. A
             narrow-gap in-vacuum undulator has been proposed to be
             installed in one of the ALS straight sections. To realize
             the optimal performance of this undulator, a straight
             section lattice with a mini vertical beta function has been
             designed. Separation of electrons has been achieved by
             generating a sizable vertical dispersion via a local
             dispersion bump and a closed orbit bump. Particle tracking
             study shows that the modified ALS lattice for the
             femto-second x-ray source has an adequate dynamic
             aperture.},
   Key = {fds191709}
}

@article{fds191710,
   Author = {V. N. Litvinenko and S. H. Park and I. V. Pinayev and Y. Wu and M.
             Emamian, N. Hower and P. Morcombe and O. Oakeley and G. Swift and P.
             Wang},
   Title = {The Deep-UV Operation of The OK-4/Duke Storage Ring
             FEL},
   Journal = {Proceedings of 1999 Particle Accelerator
             Conference},
   Pages = {221-223},
   Year = {1999},
   Abstract = {In this paper we present the result of the deep-UV lasing
             with the OK-4/Duke storage ring FEL. The OK-4 FEL was
             initially commissioned in the near-UV at Duke Free Electron
             Laboratory in November, 1996 followed by a year-long
             shutdown. After re-establishing the storage ring operation
             in early 1998, the OK-4 FEL lasing was demonstrated in the
             wavelength range of 217 to 256 nm in 1998. A number of
             lasing modes with electron energies ranging from 300 to 750
             MeV have been established to accommodate application
             research. Starting September, 1998, the coherent deep-UV
             radiation is used for applications in cornea surgery, cell
             biology, surface physics, and nuclear physics. In this paper
             we report the results of the deep-UV lasing with the
             OK-4/Duke storage ring FEL as well as our plans to advance
             towards the VUV.},
   Key = {fds191710}
}

@article{fds249278,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu, Y and Emamian, M and Hower, N and Morcombe, P and Oakeley, O and Swift, G and Wang,
             P},
   Title = {Deep-UV operation of the OK-4/Duke storage ring
             FEL},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {221-223},
   Year = {1999},
   Abstract = {In this paper we present the result of the deep-UV lasing
             with the OK-4/Duke storage ring FEL. The OK-4 FEL was
             initially commissioned in the near-UV at Duke Free Electron
             Laboratory in November, 1996 followed by a year-long
             shutdown. After re-establishing the storage ring operation
             in early 1998, the OK-4 FEL lasing was demonstrated in the
             wavelength range of 217 to 256 nm in 1998. A number of
             lasing modes with electron energies ranging from 300 to 750
             MeV have been established to accommodate application
             research. Starting September, 1998, the coherent deep-UV
             radiation is used for applications in cornea surgery, cell
             biology, surface physics, and nuclear physics. In this paper
             we report the results of the deep-UV lasing with the
             OK-4/Duke storage ring FEL as well as our plans to advance
             towards the VUV.},
   Key = {fds249278}
}

@article{fds249279,
   Author = {Morcombe, PH and Wu, Y and McGehee, R},
   Title = {Temperature sensors and controls for the Duke FEL storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2},
   Pages = {688-689},
   Year = {1999},
   Abstract = {This paper describes a prototype system used for sensing and
             control functions associated with the Duke University 1 GeV
             electron storage ring. Low cost industrial control systems
             have been used. The system is capable of handling at least
             four hundred devices.},
   Key = {fds249279}
}

@article{fds249280,
   Author = {Pinayev, IV and Detweiler, G and Emamian, M and Hower, N and Johnson, M and Litvinenko, VN and Oakley, O and Park, SH and Patterson, J and Swift, G and Wu, Y},
   Title = {Critical systems for high peak power storage ring
             FEL},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2468-2470},
   Year = {1999},
   Abstract = {The Duke storage ring is a facility dedicated for the deep
             UV free electron laser (FEL) development. It is especially
             designed for the high peak power applications, having a long
             optical cavity and large energy acceptance. In this paper we
             describe FEL gain modulator and optical cavity control
             system, which are essential for obtaining maximal peak
             power.},
   Key = {fds249280}
}

@article{fds249281,
   Author = {Wang, P and Hower, N and Litvinenko, V and Moallem, M and Oakeley, O and Swift, G and Wu, Y},
   Title = {Beam position monitors for Duke FEL storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {3},
   Pages = {2099-2101},
   Year = {1999},
   Abstract = {The Duke FEL storage ring is a 1 Gev electron ring, which is
             designed for driving UV-VUV free electron lasers. The ring
             has been in operation since November of 1994 but the beam
             position monitors (BPMs) were connected and operated just
             recently. The BPM pick-ups are 4 stripline electrodes. In
             order to reduce the higher-order-mode loss excited by the
             stored beam at the BPM pick-up area, the BPM vacuum chamber
             is designed with 4 grounding strips between the electrodes
             that have the same diameters as the electrode. This design
             allows the electron beam to see a much smoother vacuum
             chamber at the BPM area. The pick-up signals are processed
             by Bergoz's electronic modules, which give X/Y outputs
             directly. Each BPM has its own process module and 34 modules
             have been connected to the EPICS control system. The beam
             orbit now can be displayed and corrected through EPICS in
             the control room. The system performance and the test data
             will be presented in this paper.},
   Key = {fds249281}
}

@article{fds249396,
   Author = {Litvinenko, VN and Park, SH and Pinayev, IV and Wu, Y and Emamian, M and Hower, N and Morcombe, P and Oakeley, O and Swift, G and Wang,
             P},
   Title = {OK-4/Duke storage ring FEL lasing in the
             deep-UV},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {429},
   Number = {1},
   Pages = {151-158},
   Year = {1999},
   ISSN = {0168-9002},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000081126900030&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {In this paper we present the result of the deep-UV lasing
             with the OK-4/Duke storage ring FEL. The OK-4 FEL was
             initially commissioned at Duke Free Electron Laboratory in
             November 1996 followed by a yearlong shutdown. After
             re-establishing the storage ring operation in early 1998,
             the OK-4 FEL lasing was demonstrated in the wavelength range
             of 226-256 nm in April 1998. The OK-4 FEL successfully lased
             from 217 nm to 235 nm in August 1998. A number of lasing
             modes with electron energies ranging from 300 to 750 MeV
             have been established to accommodate application researches.
             Starting September 1998, the coherent deep-UV radiation is
             used for applications in surgery, cell biology, surface
             physics, and nuclear physics.},
   Doi = {10.1016/S0168-9002(99)00096-0},
   Key = {fds249396}
}

@article{fds191715,
   Author = {V. N. Litvinenko and Y. Wu},
   Title = {On Possibility of Suppression of Microwave Instability and
             Production of Femtosecond Pulses of Radiation in Storage
             Rings},
   Pages = {831-833},
   Booktitle = {Proceedings of 1998 Asia Particle Accelerator
             Conference},
   Year = {1998},
   Month = {June},
   Abstract = {The microwave instability appears to be main limiting factor
             in both longitudinal brightness of electron beam and
             achievement of very short bunches. It causes anomalous bunch
             lengthening and energy spread growth. The 6D brightness of
             electron beam is the main figure of merit for their
             applications for generation of coherent X-rays. In this
             paper a possibility to suppress or to eliminate the
             microwave instability using advanced RF system based on
             inverse sub-mm FEL is discussed [1]. We present the
             theoretical developments of strong focusing in longitudinal
             direction and discuss results of computer simulations. A
             possibility of storage ring operating with femtosecond high
             peak current electron bunches and natural energy spread is
             discussed. This beams can be used to generate both coherent
             and spontaneous X-ray beams with femtosecond duration. We
             discuss a possibility of the storage ring based FEL X-ray
             light source with average spectral brightness of 1027 -1028
             ph/sec/mm2/mrad2/0.01%BW. This value exceeds existing 3rd
             generation light sources by 6-9 orders of magnitude, making
             it a 5th generation light source.},
   Key = {fds191715}
}

@article{fds191716,
   Author = {V. N. Litvinenko and S. H. Park and Y. Wu},
   Title = {The Duke XUV FEL Storage Ring Facility},
   Pages = {834-836},
   Booktitle = {Proceedings of 1998 Asia Particle Accelerator
             Conference},
   Year = {1998},
   Abstract = {In this paper we present status and developments of the Duke
             storage ring facility. The Duke storage ring facility
             provides the unique combination of phase-locked light
             sources ranging from high power OK-4 XUV FEL to
             quasimonochromatic g -ray beam and IR/X-ray spontaneous
             radiation. The XUV OK-4 FEL, which is collaborative project
             with BINP, Novosibirsk, is in operation since November,
             1996. The OK-4 UV FEL is also used for production of nearly
             monochromatic g -ray s with tunable energy. We present the
             results of UV lasing with the OK- 4 FEL and selected results
             of its applications. We will discuss our future plans for
             extension of this source and status of the construction of
             dedicated used facility adjacent to the FEL
             building.},
   Key = {fds191716}
}

@article{fds249276,
   Author = {Litvinenko, VN and Wu, Y and Burnham, B and Park, SH and Emamian, M and Faircloth, J and Goetz, S and Hower, N and Madey, JMJ and Meyer, J and Morcombe, P and Oakeley, O and Patterson, J and Sachtschale, R and Swift, G},
   Title = {Unique features of the OK-4/Duke storage ring XUV FEL and
             monochromatic γ-ray source},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {883-885},
   Year = {1998},
   Abstract = {The OK-4 is the first storage ring FEL operating in the
             United States. It was commissioned in November, 1996 and
             demonstrated lasing in the near UV and visible ranges
             (345-413 nm) with extracted power of 0.15 W. In addition to
             lasing, the OK-4/Duke FEL generated a nearly monochromatic
             (1% FWHM) γ-ray beam. In this paper we describe the initial
             performance of the OK-4/Duke storage ring FEL and γ-ray
             source.},
   Key = {fds249276}
}

@article{fds249277,
   Author = {Lumpkin, AH and Yang, BX and Litvinenko, V and Park, S and Wang, P and Wu,
             Y},
   Title = {Initial application of a dual-sweep streak camera to the
             Duke storage ring OK-4 source},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {874-876},
   Year = {1998},
   Abstract = {The visible and UV spontaneous emission radiation (SER) from
             the Duke OK-4 wiggler has been used with a Hamamatsu C5680
             dual-sweep streak camera to characterize the stored electron
             beams. Particle beam energies of 270 and 500 MeV in the Duke
             storage ring were used in this initial application with the
             OK-4 adjusted to generate wavelengths from 500 nm to near
             200 nm. The OK-4 magnetic system with its 68 periods
             provided a much stronger radiation source than a nearby
             bending magnet source point. Sensitivity to single-bunch,
             single-turn SER was shown down to 4 μA beam current at λ =
             450 nm. The capability of seeing second passes in the FEL
             resonator at a wavelength near 200 nm was used to assess the
             cavity length versus orbit length. These tests (besides
             supporting preparation for UV-visible SR FEL startups) are
             also relevant to possible diagnostics techniques for
             single-pass FEL prototype facilities.},
   Key = {fds249277}
}

@article{fds249355,
   Author = {Lumpkin, AH and Yang, BX and Litvinenko, V and Burnham, B and Park, S and Wang, P and Wu, Y},
   Title = {Initial dual-sweep streak camera measurements on the Duke
             storage ring OK-4 UV/visible FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {407},
   Number = {1-3},
   Pages = {338-342},
   Year = {1998},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(98)00046-1},
   Abstract = {Initial measurements at the Duke storage ring free electron
             laser (FEL) of both spontaneous emission radiation (SER)
             from the OK-4 and FEL radiation outcoupled from the
             oscillator cavity have been done with a dual-sweep streak
             camera. In the SER case, ANL's Hamamatsu C5680 streak camera
             was used to characterize stored electron-beam bunch lengths
             versus rf gap voltage and single-bunch current.
             Electron-beam bunch lengths were observed in a range from 50
             to 300 ps (FWHM). Particle beam energies of 270 and 500 MeV
             in the storage ring (SR) were used with the OK-4 to generate
             SER from 500 nm to less than 200 nm. Sensitivity to
             single-bunch, single-turn SER was shown down to ∼ 4 μA
             beam current at λ = 450 nm. By operating in the synchroscan
             mode and at bunch currents less than 1 mA, beam orbit length
             vs. the resonator round-trip time was investigated by
             detecting the relative arrival time of the second pass
             outcoupled from the resonator at λ ≈ 200 nm. These
             measurements were used in support of first lasing in the
             UV-visible regime in November 1996. The dual-sweep streak
             mode was then used to monitor lasing intensity variations on
             the 1 and 50 ms time scales, to measure a lasing pulse
             length as short as ∼ 3 ps (σ) at λ = 388 nm at low beam
             current, and to track the orbit length detuning curve. ©
             1998 Published by Elsevier Science B.V. All rights
             reserved.},
   Doi = {10.1016/S0168-9002(98)00046-1},
   Key = {fds249355}
}

@article{fds249356,
   Author = {Park, SH and Litvinenko, VN and Burnham, B and Wu, Y and Madey, JMJ and Canon, RS and Howell, CR and Roberson, NR and Schreiber, EC and Spraker,
             M and Tornow, W and Weller, HR and Pinayev, IV},
   Title = {OK-4/Duke monochromatic γ-ray source: Performance and
             prediction},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {407},
   Number = {1-3},
   Pages = {224-228},
   Year = {1998},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(97)01400-9},
   Abstract = {A beam of nearly monochromatic γ-rays was produced via
             intracavity Compton backscattering in the OK-4/Duke storage
             ring FEL. The OK-4 FEL operated in the near-UV range
             (345-413 nm) with electron energies of 260-550 MeV. The
             energy of the produced γ-rays varied from 3 to 16 MeV. In
             the near future we plan to increase the energy of the
             γ-rays to 50 MeV by increasing the electron energy and
             reducing FEL wavelength. Results from direct measurements of
             the γ-ray flux and energy resolution (using a 3 mm diameter
             lead collimator) (Litvinenko et al., Phys. Rev. Lett. 78
             (1997) 4569) are very close to our theoretical predictions.
             The energy resolution of the γ-rays was ∼ 1%. In this
             paper we present a comparison of our measurements with
             theoretical predictions and our plans for future
             improvements. We discuss upgrades of our system to attain an
             energy resolution down to 0.1% and to increase the flux. A
             brief description of the experimental program utilizing the
             OK-4/Duke monochromatic γ-ray source is presented. © 1998
             Elsevier Science B.V. All rights reserved.},
   Doi = {10.1016/S0168-9002(97)01400-9},
   Key = {fds249356}
}

@article{fds249357,
   Author = {Litvinenko, VN and Burnham, B and Park, SH and Wu, Y and Cataldo, R and Emamian, M and Faircloth, J and Goetz, S and Hower, N and Madey, JMJ and Meyer, J and Morcombe, P and Oakeley, O and Patterson, J and Swift, G and Wang, P and Pinayev, IV and Fedotov, MG and Gavrilov, NG and Popik, VM and Repkov, VN and Isaeva, LG and Kulipanov, GN and Kurkin, GY and Mikhailov, SF and Skrinsky, AN and Vinokurov, NA and Vobly, PD and Lumpkin, A and Yang, B},
   Title = {First UV/visible lasing with the OK-4/Duke storage ring
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {407},
   Number = {1-3},
   Pages = {8-15},
   Year = {1998},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/S0168-9002(97)01357-0},
   Abstract = {In this paper, we report first lasing results in the near-UV
             and visible spectral ranges with the OK-4/Duke storage ring
             - the first storage ring FEL operating in the United States.
             The OK-4/Duke FEL was commissioned in November 1996 and
             demonstrated lasing in the 345-413 nm range with extracted
             power of 0.15 W. In addition to lasing, the OK-4/Duke FEL
             generated a nearly monochromatic (1% FWHM) γ-ray beams. In
             this paper, we describe initial performance of the OK-4/Duke
             storage ring FEL and γ-ray source in this demonstration
             experiment. We briefly discuss the present status of the
             project and its future user program. © 1998 Published by
             Elsevier Science B.V. All rights reserved.},
   Doi = {10.1016/S0168-9002(97)01357-0},
   Key = {fds249357}
}

@article{fds249358,
   Author = {Wu, Y and Litvinenko, VN and Pinayev, IV and Park, SH and Burnham,
             B},
   Title = {Duke FEL storage ring light sources and applications},
   Journal = {Nuclear Instruments and Methods in Physics Research, Section
             B: Beam Interactions with Materials and Atoms},
   Volume = {144},
   Number = {1-4},
   Pages = {90-98},
   Year = {1998},
   Abstract = {In this paper we present the status of the Duke UV FEL (Free
             Electron Laser) storage ring, ring based light sources, and
             a related multi-disciplinary application program. Using the
             OK-4 optical klystron system, we have demonstrated tunable
             spontaneous radiation from the near Infrared (IR) to UV,
             coherent laser radiation from 345 to 413 nm, and Compton
             back-scattered linearly polarized γ-ray radiation from 3 to
             16 MeV. We report the progress made in developing new light
             source capabilities. We also report user interface
             development for a pilot application program organized to
             utilize various ring driven sources. We discuss future
             upgrades and additions to the ring based sources. © 1998
             Elsevier Science B.V. All rights reserved.},
   Key = {fds249358}
}

@article{fds249359,
   Author = {Ade, H and Yang, W and English, SL and Hartman, J and Davis, RF and Nemanich, RJ and Litvinenko, VN and Pinayev, IV and Wu, Y and Madey,
             JMJ and Litvinenko, VN and Pinayev, IV and Wu, Y and Madey,
             JMJ},
   Title = {A free electron laser-photoemission electron microscope
             system (FEL-PEEM)},
   Journal = {Surface Review and Letters},
   Volume = {5},
   Number = {6},
   Pages = {1257-1268},
   Year = {1998},
   Abstract = {We report first results from our effort to couple a high
             resolution photoemission electron microscope (PEEM) to the
             OK-4 ultraviolet free electron laser at Duke University
             (OK-4/Duke UV FEL). The OK-4/Duke UV PEL is a high intensity
             source of tunable monochromatic photons in the 3-10 eV
             energy range. This tunability is unique and allows us to
             operate near the photoemission threshold of any samples and
             thus maximize sample contrast while keeping chromatic
             aberrations in the PEEM minimal. We have recorded first
             Images from a variety of samples using spontaneous radiation
             from the OK-4/Duke UV PEL in the photon energy range of
             4.0-6.5 eV. Due to different photothreshold emission from
             different sample areas, emission from these areas could be
             turned on (or off) selectively. We have also observed
             relative intensity reversal with changes in photon energy
             which are interpreted as density-of-state contrast. Usable
             image quality has been achieved, even though the output
             power of the FEL in spontaneous emission mode was several
             orders of magnitude lower than the anticipated full laser
             power. The PEEM has achieved a spatial resolution of 12
             nm.},
   Key = {fds249359}
}

@article{fds292656,
   Author = {Pinayev, IV and Emamian, M and Litvinenko, VN and Park, SH and Wu,
             Y},
   Title = {System for the control and stabilizing of OK-4/Duke FEL
             optical cavity},
   Journal = {AIP Conference Proceedings},
   Volume = {451},
   Pages = {545-551},
   Booktitle = {AIP Conf. Proceedings 451},
   Year = {1998},
   ISBN = {1-56396-794-4},
   ISSN = {0094-243X},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000078034100062&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {The control system of an optical cavity is described. Usage
             of the piezoelectric actuators and position sensitive
             photodetectors in this system allows us to reach a
             resolution at a submicroradian level and to suppress mirror
             vibrations below 50 Hz.},
   Doi = {10.1063/1.57040},
   Key = {fds292656}
}

@article{fds249275,
   Author = {Litvinenko, VN and Wu, Y and Burnham, B and Park, SH and Emamian, M and Faircloth, J and Goetz, S and Hower, N and Madey, JMJ and Meyer, J and Morcombe, P and Oakeley, O and Patterson, J and Sachtschale, R and Swift, G and Wang, P and Pinayev, IV and Fedotov, MG and Gavrilov, NG and Popik, VM and Repkov, VN and Isaeva, LG and Kulipanov, GN and Kurkin,
             GY and Mikhailov, SF and Skrinsky, AN and Vinokurov, NA and Vobly, PD and Zinin, EI and Lumpkin, AH and Yang, BX},
   Title = {First UV/visible lasing with the OK-4/Duke storage ring FEL:
             Design and initial performance},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {2988},
   Pages = {188-199},
   Booktitle = {Free-Electron Laser Challenges},
   Year = {1997},
   ISSN = {0277-786X},
   url = {http://dx.doi.org/10.1117/12.274393},
   Abstract = {The OK-4/Duke storage ring FEL was commissioned in November
             1996 and demonstrated lasing in the near UV and visible
             ranges (345 - 413 nm). The OK-4 is the first storage ring
             FEL with the shortest wavelength and highest power for UV
             FELs operating in the United States. During one month of
             operation we have performed preliminary measurements of the
             main parameters of the OK-4 FEL: its gain, lasing power and
             temporal structure. In addition to lasing, the OK-4/Duke FEL
             generated a nearly monochromatic (1% FWHM) 12.2 MeV
             gamma-ray beam. In this paper we describe the design and
             initial performance of the OK-4/Duke storage ring FEL. We
             compare our predictions with lasing results. Our attempt to
             lase in the deep UV range (around 193 nm) is discussed. The
             OK-4 diagnostic systems and performance of its optical
             cavity are briefly described. ©2005 Copyright SPIE - The
             International Society for Optical Engineering.},
   Doi = {10.1117/12.274393},
   Key = {fds249275}
}

@article{fds249343,
   Author = {Burnham, B and Litvinenko, VN and Wu, Y and Park, SH and Cataldo, R and Emamian, M and Hower, N and Madey, JMJ and Morcombe, P and Oakeley, O and Swift, G and Wang, P and Pinayev, IV and Popik, VM and Kulipanov, GN and Mikhailov, SF and Skrinsky, AN and Vinokurov, NA and Lumpkin, A and Yang, B},
   Title = {Status of the OK-4/Duke university storage ring XUV
             FEL},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {3154},
   Pages = {64-71},
   Year = {1997},
   url = {http://dx.doi.org/10.1117/12.293371},
   Abstract = {The OK-4/Duke storage ring free electron laser (FEL) was
             commissioned in November, 1996 and demonstrated lasing in
             the near UV and visible ranges (345-413 nm). During one
             month of operation we performed preliminary measurements of
             the main parameters of the OK-4 FEL: its gain, lasing power
             and temporal structure. In addition to lasing, the OK-4/Duke
             FEL generated a nearly monochromatic (1% FWHM) 12.2 MeV
             γ-ray beam1. In this paper we describe the status of the
             main subsystems including the injector system and the ring
             itself, and discuss future and in-progress upgrades to these
             systems. We also describe the parameters measured to date of
             the injector, the storage ring, the generated optical laser
             beams, and the backscattered γ-ray beam.},
   Doi = {10.1117/12.293371},
   Key = {fds249343}
}

@article{fds249353,
   Author = {Wu, Y and Litvinenko, VN and Burnham, B and Park, SH and Madey,
             JMJ},
   Title = {Performance and operation modes of the duke PEL storage
             ring},
   Journal = {IEEE Transactions on Nuclear Science},
   Volume = {44},
   Number = {5},
   Pages = {1753-1759},
   Year = {1997},
   ISSN = {0018-9499},
   url = {http://dx.doi.org/10.1109/23.633429},
   Abstract = {We present the recent status and performance of the Duke
             Free Electron Laser (PEL) storage ring. We report a large
             transverse and energy aperture observed in the storage ring.
             We describe the consequences of this large aperture on the
             operation of the storage ring. Several unusual phenomena are
             reported in this paper, including large amplitude transverse
             multibunch coherent oscillations (Saturn rings) and beam
             capture from outside the RF separatrix. We also present the
             established operation modes for the storage ring, including
             energy ramping, working point tuning, and different
             bunch-mode operations to optimize the ring as a synchrotron
             light source, an PEL, and a gamma-ray source. Finally, we
             summarize the achieved storage ring parameters since its
             first operation in November 1994. © 1997
             IEEE.},
   Doi = {10.1109/23.633429},
   Key = {fds249353}
}

@article{fds249354,
   Author = {Litvinenko, VN and Burnham, B and Emamian, M and Hower, N and Madey,
             JMJ and Morcombe, P and O'Shea, PG and Park, SH and Sachtschale, R and Straub, KD and Swift, G and Wang, P and Wu, Y and Canon, RS and Howell, CR and Roberson, NR and Schreiber, EC and Spraker, M and Tornow, W and Weller,
             HR and Pinayev, IV and Gavrilov, NG and Fedotov, MG and Kulipanov, GN and Kurkin, GY and Mikhailov, SF and Popik, VM and Skrinsky, AN and Vinokurov, NA and Norum, BE and Lumpkin, A and Yang,
             B},
   Title = {Gamma-ray production in a storage ring free-electron
             laser},
   Journal = {Physical Review Letters},
   Volume = {78},
   Number = {24},
   Pages = {4569-4572},
   Year = {1997},
   Abstract = {A nearly monochromatic beam of 100% linearly polarized γ
             rays has been produced via Compton backscattering inside a
             free electron laser optical cavity. The beam of 12.2 MeV γ
             rays was obtained by backscattering 379.4 nm free-electron
             laser photons from 500 MeV electrons circulating in a
             storage ring. A detailed description of the γ-ray beam and
             the outlook for future improvements are presented.},
   Key = {fds249354}
}

@article{fds191723,
   Author = {B. Burnham and V. N. Litvinenko and J. M. J. Madey and Y.
             Wu},
   Title = {Microbunching in Storage Ring FELs},
   Journal = {Proceedings of Micro Bunches Workshop, Editors: E. B. Blum,
             M. Dienes, J. B. Murphy},
   Volume = {367},
   Pages = {215--224},
   Booktitle = {AIP Conf. Proceedings},
   Year = {1996},
   Abstract = {We propose two schemes to create short electron bunches
             within a storage ring free electron laser (FEL). The first
             scheme proposed will operate a nearly isochronous ramwave
             FEL at the Duke storage ring facility. Resonant FEL
             conditions for the nun-wave will be provided by the off-axis
             interaction with an electromagnetic wave. Simulation results
             for the proposed mm-wave FEL operation on the Duke storage
             ring will be discussed. The second proposal is to maintain
             electron structure on an optical wave scale by operating the
             storage ring on a high order resonance in order to produce
             FEL power above the random phase approximation. The high
             order resonance will be used to compensate for the natural
             dispersion and loss of phase information. An N-th order
             resonance will restore phase information after N turns of
             the electron bunch in the storage ring. In this mode, which
             does not require isochronicity of the ring, the stochastic
             conditions used to derive the random phase approximation are
             no longer applicable.},
   Key = {fds191723}
}

@article{fds249350,
   Author = {O'Shea, PG and Litvinenko, VN and Madey, JMJ and Roberson, NR and Schreiber, EC and Straub, KD and Weeks, KJ and Weller, HR and Wu,
             Y},
   Title = {Inverse Compton γ-ray source for nuclear physics and
             related applications},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {375},
   Number = {1-3},
   Pages = {530-534},
   Year = {1996},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/0168-9002(96)00052-6},
   Abstract = {The development of intense, short-wavelength FEL light
             sources has opened opportunities for new applications of
             high-energy Compton-backscattered photons. These
             applications range from medical imaging with X-rays to high
             energy physics with photon colliders. In this paper we
             discuss the practical aspects applications using polarized
             Compton backscattered γ-rays in the 5-150 MeV range from
             the Duke storage-ring-driven FEL. Such applications include:
             nuclear physics, cancer therapy, radiographic imaging,
             radiation effects testing, and positron production for
             material science studies.},
   Doi = {10.1016/0168-9002(96)00052-6},
   Key = {fds249350}
}

@article{fds249351,
   Author = {Litvinenko, VN and Burnham, B and Madey, JMJ and Park, SH and Wu,
             Y},
   Title = {Duke storage ring UV/VUV FEL: Status and
             prospects},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {375},
   Number = {1-3},
   Pages = {46-52},
   Year = {1996},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/0168-9002(95)01471-3},
   Abstract = {A 1.1 GeV electron storage ring dedicated for UV-VUV FEL
             operation was commissioned last year at the Duke University
             Free Electron Laser Laboratory [VN. Litvinenko et al.,
             Commissioning of the Duke storage ring, Proc. 1995 Particle
             Accelerator Conf., Dallas, TX, May 1-5, 1995]. The XUV FEL
             project, based on the collaboration of the Duke FEL
             Laboratory and Budker Institute for Nuclear Physics
             (Novosibirsk, Russia) is described. The OK-4 UV FEL has
             arrived from Novosibirsk at the Duke FEL laboratory and is
             in the process of installation. The main parameters of the
             Duke Free Electron Laser Laboratory (DFELL) storage ring,
             the OK-4 optical klystron, and the experimental set-up are
             presented. The parameters of the UV-VUV FEL are given and
             possible future upgrades to this system are discussed. We
             have developed a new macro-particle code for storage ring
             simulation including all known mechanisms of storage ring
             FEL interaction. We confirm our expectations on the average
             and peak power for the OK-4. In addition we have studied a
             giant pulse mode of operation. A new mechanism of
             "super-pulse" generation was discovered during these
             studies. It allows the generation of peak power up to 10 GW
             using "phase-space" refreshment of the electron beam caused
             by synchrotron motion [V.N. Litvinenko, B. Burnham, J.M.J.
             Madey and Y. Wu, Nucl. Instr. and Meth. A 358 (1995)
             334].},
   Doi = {10.1016/0168-9002(95)01471-3},
   Key = {fds249351}
}

@article{fds249352,
   Author = {Wu, Y and Litvinenko, VN and Burnham, B and Madey, JMJ and Park,
             SH},
   Title = {The performance of the Duke FEL storage ring},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {375},
   Number = {1-3},
   Pages = {74-77},
   Year = {1996},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/0168-9002(95)01473-X},
   Abstract = {Commissioning of the Duke FEL storage ring has been
             completed successfully. During commissioning and initial
             operation, a series of performance measurements were
             performed on the storage ring. In this paper we discuss the
             techniques used in the measurements, present the
             measurements results, and compare the measured parameters
             with the design specifications.},
   Doi = {10.1016/0168-9002(95)01473-X},
   Key = {fds249352}
}

@article{fds292657,
   Author = {Burnham, B and Litvinenko, VN and Madey, JMJ and Wu,
             Y},
   Title = {Microbunching in storage ring},
   Journal = {AIP Conference Proceedings},
   Number = {367},
   Pages = {215-224},
   Year = {1996},
   ISBN = {1-56396-555-0},
   ISSN = {0094-243X},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1996BF35Z00020&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Key = {fds292657}
}

@article{fds191722,
   Author = {Y. Wu and B. Burnham and V. N. Litvinenko},
   Title = {The Duke Storage Ring Control System},
   Journal = {Proceedings of 1995 Particle Accelerator
             Conference},
   Pages = {2214-2216},
   Year = {1995},
   Abstract = {The Duke storage ring is a dedicated facility for the UV-VUV
             FEL operation. The low level computer control system for the
             Duke storage ring is developed using EPICS. The control
             hardware employs several different architectures including
             CAMAC, GPIB, Allen Bradley, and VME. The high level control
             is implemented in Tcl-Tk scripts running on SPARCstations.
             Tcl- Tk provides the global control capabilities such as the
             energy ramping, the orbit compensation, and the tune and
             chromaticity control. The Duke storage ring control system
             was tested and operational for storage ring commissioning in
             Nov. 1994. During commissioning, additional control tools
             were developed to facilitate the operation.},
   Key = {fds191722}
}

@article{fds249268,
   Author = {Wang, P and Morcombe, P and Wu, Y},
   Title = {RF system for the Duke 1 GeV storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {3},
   Pages = {1841-1842},
   Year = {1995},
   Abstract = {The RF frequency is 178.5 MHz. An amplifier built by the QEI
             corporation provides 50 KW power. All the power feeds to a
             single-cell RF cavity, built by BINP at Novosibirsk, Russia,
             giving a gap voltage of 720 KV. An ANT circulator is used in
             the feed line. There are four basic feed-back loops to
             stabilize the system operation : 1) Cavity frequency tuning
             loop. 2) Cavity voltage control loop. 3) RF phase
             stabilization loop. 4) Synchrotron oscillation damping loop.
             The whole system has been tested and operated since December
             1993. It has provided secure and stable operation for the
             storage ring.},
   Key = {fds249268}
}

@article{fds249269,
   Author = {Burnham, B and Litvinenko, VN and Wu, Y},
   Title = {Application of precision magnetic measurements for control
             of the Duke storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {524-526},
   Year = {1995},
   Abstract = {The 1 GeV Duke storage ring is designed to drive UV and VUV
             free electron laser devices. Specifics of this ring include
             the use of combined function magnets: quadrupole-sextupole
             and dipole-sextupole. The close spacing of magnetic elements
             required the use of these combined function magnets. A
             discussion on the measurement of these magnets is included,
             as well as the data analysis used to create a viable control
             system for the combined function magnets.},
   Key = {fds249269}
}

@article{fds249270,
   Author = {Litvinenko, VN and Burnham, B and Hower, N and Morcombe, P and Wu,
             Y},
   Title = {Duke storage ring tune measurements system using razor blade
             and photomultiplier},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2461-2463},
   Year = {1995},
   Abstract = {We present in this paper the description of the Duke storage
             ring tune measurements system. An unusual feature of this
             system is the use of synchrotron radiation to sense
             oscillation of the electron beam. This system includes a
             lens, a razor blade placed at the focus and a
             photomultiplier. Our experience shows that this system can
             operate on -70 dBm level and detect electron beam
             oscillations as small as one micron.},
   Key = {fds249270}
}

@article{fds249271,
   Author = {Wu, Y and Litvinenko, VN and Burnham, B and Madey,
             JMJ},
   Title = {Experimental study of the Duke storage ring dynamic
             aperture},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {5},
   Pages = {2877-2879},
   Year = {1995},
   Abstract = {The Duke storage ring was designed with a large dynamic
             aperture for UV-VUV Free Electron Laser (FEL) operations.
             During commissioning of the Duke storage ring, experiments
             were performed to measure the horizontal, vertical, and
             energy apertures. The experimental methods used for the
             aperture measurements are presented in this paper. The
             measured results are discussed and compared with the
             computer simulations.},
   Key = {fds249271}
}

@article{fds249272,
   Author = {Dickey, C and Burnham, B and Carter, F and Fricks, R and Litvinenko, V and Nagchaudhuri, A and Morcombe, P and Pantazis, R and O'Shea, P and Sachtschale, R and Wu, Y},
   Title = {EPICS at Duke University},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2217-2219},
   Year = {1995},
   Abstract = {Since the last Particle Accelerator Conference, the
             Experimental Physics and Industrial Control System (EPICS)
             has been utilized for control system development and
             implementation on several accelerators that have recently
             been commissioned at the Free Electron Laser Laboratory
             which is operated under the auspices of the Physics
             Department at Duke University. The historic Mark III
             infrared free electron laser formerly located at Stanford
             University, a recently designed and constructed 280 MeV
             electron linear accelerator and a 1 GeV storage ring
             synchrotron are now operating under EPICS control.
             Commissioning of the new injection linac and the storage
             ring has gone extremely well. The authors feel that through
             the employment of a standard controls development
             environment such as EPICS, considerable amounts of
             resources, both financial and human, have been saved. The
             authors note generally positive experiences with EPICS. The
             highlights of these experiences, as well as some suggestions
             for future improvements will be presented in the body of
             this report.},
   Key = {fds249272}
}

@article{fds249273,
   Author = {Litvinenko, VN and Wu, Y and Burnham, B and Madey, JMJ and Carter, F and Dickey, C and Emamian, M and Gustavsson, J and Hower, N and Morcombe, P and Park, SH and O'Shea, P and Sachtshale, R and Straub, D and Swift,
             G},
   Title = {Commissioning of the Duke Storage Ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {213-215},
   Year = {1995},
   Abstract = {The commissioning of the 1 GeV Duke Storage Ring began in
             November, 1994 with the demonstration of injection, storage
             and ramping to 1 GeV at the first attempt. The ring is now
             operational. The Duke project is unique in that the storage
             ring and linac were designed, constructed and commissioned
             by a small new University laboratory, operating on a low
             budget. The team is comprised of six accelerator physicists
             and graduate students, eight engineers, and fifteen
             technicians.},
   Key = {fds249273}
}

@article{fds249274,
   Author = {Wu, Y and Burnham, B and Litvinenko, VN},
   Title = {Duke storage ring control system},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2214-2216},
   Year = {1995},
   Abstract = {The Duke storage ring is a dedicated facility for the UV-VUV
             FEL operation. The low level computer control system for the
             Duke storage ring is developed using EPICS. The control
             hardware employs several different architectures including
             CAMAC, GPIB, Allen Bradley, and VME. The high level control
             is implemented in Tcl-Tk scripts running on SPARCstations.
             Tcl-Tk provides the global control capabilities such as the
             energy ramping, the orbit compensation, and the tune and
             chromaticity control. The Duke storage ring control system
             was tested and operational for storage ring commissioning in
             Nov. 1994. During commissioning, additional control tools
             were developed to facilitate the operation.},
   Key = {fds249274}
}

@article{fds249334,
   Author = {Litvinenko, VN and Wu, Y and Burnham, B and Madey, JMJ and Park,
             SH},
   Title = {Performance of achromatic lattice with combined function
             sextupoles at Duke storage ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2},
   Pages = {796-798},
   Year = {1995},
   Abstract = {The 1 GeV Duke Storage Ring was very successfully
             commissioned with performance exceeding initial
             specifications. In this paper we present design and
             performance data of its unique achromatic lattice with
             combined function magnets in the ring arcs.},
   Key = {fds249334}
}

@article{fds249335,
   Author = {O'Shea, PG and Carter, F and Dickey, C and Hower, N and Litvinenko, VN and Sachtschale, R and Swift, G and Wang, P and Wu, Y and Madey,
             JMJ},
   Title = {Accelerator archeology - the resurrection of the Stanford
             MarkIII electron linac at Duke},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {2},
   Pages = {1090-1092},
   Year = {1995},
   Abstract = {In the early 1960s, the Mark III accelerator at the Stanford
             High Energy Physics Laboratory was used as the prototype
             test-bed for the SLAC Two-Mile accelerator. In the mid 1980s
             the accelerator was dismantled and a large part of it was
             transported to the Duke University Free-Electron Laser
             Laboratory to form the basis of the injector for the 1-GeV
             Duke Storage Ring. The plan was to use the original
             accelerator sections and some rf equipment with new magnetic
             optics, vacuum system, gun and a modern control system. The
             first 295-MeV portion of the linac is now operational at
             Duke. The linac currently consists of eleven sections from
             the old linac with a single-cell rf gun. Our guiding
             principal has been one of economy and simplicity. We have
             not attempted to restore the accelerator to its original
             form, but have added modern components where necessary. We
             discuss some of the more interesting features of the linac,
             and how we have given new life to this venerable machine
             here at Duke.},
   Key = {fds249335}
}

@article{fds249340,
   Author = {Litvinenko, VN and Wu, Y and Burnham, B and Barnett, GA and Madey,
             JM},
   Title = {Picosecond, tunable, high-brightness hard x-ray inverse
             Compton source at Duke storage ring},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {2521},
   Pages = {2-12},
   Year = {1995},
   ISSN = {0277-786X},
   Abstract = {We suggest a state-of-the art x-ray source using a compact
             electron storage ring with modest energy (less than 1 GeV)
             and a high power mm-wave as an undulator. A source of this
             type has x-ray energies and brightness comparable with third
             generation synchrotron light sources while it can be very
             compact and fit in a small university or industrial
             laboratory or hospital. We propose to operate an isochronous
             mm-wave FEL and a hard x-ray inverse Compton source at the
             Duke storage ring to test this concept. Resonant FEL
             conditions for the mm- wave will be provided by the off-axis
             interaction with an electromagnetic wave. A special optical
             resonator with holes for the e-beam is proposed for pumping
             a hard x-ray inverse Compton source with very high
             brightness. Simulation results of mm-wave FEL operation of
             the Duke storage ring are discussed. Expected performance of
             mm-wave FEL and hard x-ray inverse Compton source are
             presented.},
   Key = {fds249340}
}

@article{fds249341,
   Author = {Litvinenko, VN and Barnett, GA and Burnham, B and Hower, N and Johnson,
             L and Madey, JM and Wu, Y},
   Title = {Short-wavelength light sources at Duke storage
             ring},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {2522},
   Pages = {473-482},
   Year = {1995},
   ISSN = {0277-786X},
   Abstract = {A 1.1 GeV electron storage ring is now fully operational at
             the Duke University Free Electron Laser Laboratory. This
             ring is dedicated to drive a variety of very high brightness
             short- wavelength sources ranging from UV to gamma-rays. In
             this paper we present overview of short-wavelength radiation
             sources including THE OK-4 (XUV FEL, wiggler radiation and
             inverse Compton γ-rays), X-ray bend-magnets synchrotron
             radiation, soft X-ray NIST undulator radiation and hard
             X-ray inverse Compton source. We also describe status of the
             sources and our short-term and long-term
             plans.},
   Key = {fds249341}
}

@article{fds249342,
   Author = {Litvinenko, VN and Burnham, B and Madey, JM and Wu,
             Y},
   Title = {High peak pulse power operation of the OK-4/Duke XUV
             FEL},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {2521},
   Pages = {78-89},
   Year = {1995},
   ISSN = {0277-786X},
   Abstract = {A 1 GeV electron storage ring dedicated for UV-VUV FEL
             operation was commissioned last year at the Duke University
             Free Electron Laser Laboratory. The XUV FEL project, based
             on the collaboration of the Duke FEL Laboratory and Budker
             Insititute for Nuclear Physics (Novosibirsk, Russia) is
             described. The OK-4 UV FEL has arrived from Novosibirsk at
             the Duke FEL laboratory and is in the process of
             installation. The main parameters of the DFELL storage ring,
             the OK-4 optical klystron, and the experimental set-up are
             presented. The parameters of the UV-VUV FEL are given and
             the possible future upgrades to this system are discussed.
             We have studied the dynamics of giant pulse generation in
             the Duke/OK-4 UV FEL. We have developed a new macro-particle
             code for giant pulse simulation including all known
             mechanisms of storage ring FEL interaction. Results of these
             giant pulse simulations are presented in the paper. A new
             mechanism of 'super-pulse' generation was discovered during
             these studies. It allows the generation of peak power up to
             10 gigawatts using 'phase- space' refreshment of the
             electron beam caused by synchrotron motion.},
   Key = {fds249342}
}

@article{fds249346,
   Author = {Litvinenko, VN and Burnham, B and Madey, JMJ and Wu,
             Y},
   Title = {Dynamics of the Duke storage ring UV FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {358},
   Number = {1-3},
   Pages = {369-373},
   Year = {1995},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/0168-9002(94)01575-9},
   Abstract = {The Duke 1 GeV storage ring will be commissioned this year
             with a 280 MeV linac-injector. We intend to ramp the energy
             to 0.7-1.0 GeV for FEL operation. The OK-4 optical klystron
             will be shipped from the Budker Institute of Nuclear Physics
             to Duke in early 1995. The OK-4 will be the first FEL to
             operate on the Duke storage ring. This paper is dedicated to
             the study of the OK-4 performance in the CW mode of
             operation in the UV range, using a 3-D code developed by the
             authors. © 1995.},
   Doi = {10.1016/0168-9002(94)01575-9},
   Key = {fds249346}
}

@article{fds249347,
   Author = {Litvinenko, VN and Burnham, B and Madey, JMJ and Wu,
             Y},
   Title = {Giant laser pulses in the Duke storage ring UV
             FEL},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {358},
   Number = {1-3},
   Pages = {334-337},
   Year = {1995},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/0168-9002(94)01290-3},
   Abstract = {We have studied the dynamics of giant pulse generation in
             the Duke UV FEL with peak power of several gigawatts. The
             giant pulses will be provided by a FEL gain modulation
             technique developed for the OK-4 UV FEL at Novosibirsk,
             Russia. A new mechanism for "super-pulse" generation was
             discovered during these studies. It allows the generation of
             peak power up to 10 GW using the "phase space" refreshment
             of the electron beam caused by synchrotron motion [V.
             Litvinenko et al., to be published]. We have developed a new
             macro-particle code for giant pulse simulation including all
             known mechanisms of storage ring FEL interaction. Results of
             these giant pulse simulations are presented in the paper. ©
             1995.},
   Doi = {10.1016/0168-9002(94)01290-3},
   Key = {fds249347}
}

@article{fds249348,
   Author = {Litvinenko, VN and Wu, Y and Burnham, B and Madey,
             JMJ},
   Title = {Expected performance of the mm-wave isochronous FEL at the
             Duke storage ring},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {358},
   Number = {1-3},
   Pages = {349-352},
   Year = {1995},
   ISSN = {0168-9002},
   Abstract = {We propose to operate an isochronous mm-wave FEL at the Duke
             storage ring. Resonant FEL conditions for mm-waves will be
             provided by the off-axis interaction with an electromagnetic
             wave. The intracavity power of the mm-wave FEL could be used
             to pump a hard X-ray inverse Compton source with very high
             brightness. This is discussed in a separate contribution to
             these proceedings. Simulation results of mm-wave FEL
             operation on the Duke storage ring are discussed. The
             expected performance of a mm-wave FEL is presented. ©
             1995.},
   Key = {fds249348}
}

@article{fds249349,
   Author = {Litvinenko, VN and Wu, Ỳ and Burnham, B and Barnett, G and Madey,
             JMJ},
   Title = {mm-wave isochronous FEL and hard X-ray inverse Compton
             source at the Duke storage ring},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {358},
   Number = {1-3},
   Pages = {345-348},
   Year = {1995},
   ISSN = {0168-9002},
   url = {http://dx.doi.org/10.1016/0168-9002(94)01414-0},
   Abstract = {We propose to operate an isochronous mm-wave FEL at the Duke
             storage ring. Resonant FEL conditions for mm-waves will be
             provided by the off-axis interaction with an electromagnetic
             wave. A special optical resonator with holes for the e-beam
             is proposed for pumping a hard X-ray inverse Compton source
             with very high brightness. Simulation results for proposed
             mm-wave FEL operation on the Duke storage ring are discussed
             in a separate article in these proceedings. The expected
             performance of the hard X-ray inverse Compton source is
             presented. © 1995.},
   Doi = {10.1016/0168-9002(94)01414-0},
   Key = {fds249349}
}

@article{fds191733,
   Author = {S. Kramer and Y. Wu and V. N. Litvinenko and C. B. Mckee and B.
             Burnham},
   Title = {Bunch Current Density Measurements in the VUV Light
             Source},
   Journal = {Proceedings of 4th European Particle Accelerator Conference
             (EPAC1994)},
   Pages = {1696-1698},
   Year = {1994},
   Abstract = {Recentm easurementosf the bunch current density in the VUV
             storage ring at the National Synchrotron Light Source have
             been made from a stripline using a new technology of a
             realtime oscilloscope with bandwidth up to 5 GHz. A
             deconvolution technique has been developed to reconstruct
             the bunch current distribution in the longitudinal
             direction. The non-Gaussian lengthened bunch profiles at
             high currents and with a 4th harmonic RF systema rc
             reconstructed.},
   Key = {fds191733}
}

@article{fds249345,
   Author = {Wu, Y and Litvinenko, VN and Madey, JMJ},
   Title = {Study of undulator influence on the dynamic aperture for the
             Duke FEL storage ring},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {341},
   Number = {1-3},
   Pages = {363-366},
   Year = {1994},
   ISSN = {0168-9002},
   Abstract = {The Duke FEL storage ring is designed to accommodate FEL
             undulators with a maximum length of 26 m. We present the
             study of undulator influence on the dynamic aperture for the
             OK-4 FEL and the future 26 m FEL. © 1994.},
   Key = {fds249345}
}

@article{fds249265,
   Author = {Burnham, B and Hower, N and Litvinenko, VN and Madey, JMJ and Wu,
             Y},
   Title = {Specific features of magnet design for the Duke FEL storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {4},
   Pages = {2889-2891},
   Year = {1993},
   Abstract = {The 1 GeV Duke free electron laser (FEL) storage ring is
             dedicated to drive UV and VUV free electron laser devices.
             The high brightness and low emittance electron beams needed
             for these devices demand high performance and tolerances on
             the storage ring magnet lattice. This paper discusses how
             the combined function magnets are used to eliminate discrete
             elements and odd shaped end pieces which can cause magnetic
             coupling saturation and severe undesirable field
             nonlinearities. Also included is a discussion of a
             nonstandard septum magnet with stray field compensation
             which will be employed by this storage ring.},
   Key = {fds249265}
}

@article{fds249267,
   Author = {Wu, Y and Litvinenko, VN and Madey, JMJ},
   Title = {Lattice and dynamic aperture of the Duke FEL storage
             ring},
   Journal = {Proceedings of the IEEE Particle Accelerator
             Conference},
   Volume = {1},
   Pages = {218-220},
   Year = {1993},
   Abstract = {A low emittance lattice of the Duke FEL (Free Electron
             Laser) storage ring dedicated to drive UV-VUV FELs is
             presented. The second order geometrical aberration is
             compensated to increase the dynamic aperture. The 6-D
             dynamic aperture study has been performed on this lattice
             using symplectic tracking codes, which demonstrates a large
             energy aperture. The influences of higher-order multipoles
             (HMs), RMS errors and 6.8-m OK-4 undulator on dynamic
             aperture are studied. The transverse dynamic aperture is
             mainly limited by HMs in the straight section quadrupoles.
             For future FEL operations, we have designed a new straight
             section lattice for a 26-m long FEL undulator. The dynamic
             aperture for this lattice is discussed.},
   Key = {fds249267}
}

@article{fds249344,
   Author = {Wu, Y and Litvinenko, VN and Forest, E and Madey,
             JMJ},
   Title = {Dynamic aperture study for the Duke FEL storage
             ring},
   Journal = {Nuclear Instruments and Methods in Physics Research Section
             A: Accelerators, Spectrometers, Detectors and Associated
             Equipment},
   Volume = {331},
   Number = {1-3},
   Pages = {287-292},
   Year = {1993},
   ISSN = {0168-9002},
   Abstract = {The new lattice design of the Duke free electron laser (FEL)
             storage ring is described. The results of the 6-dimensional
             dynamic aperture study using single particle tracking codes
             are presented. The influence of 8-m FEL undulator on the
             dynamic aperture is studied. © 1993.},
   Key = {fds249344}
}

@article{fds304632,
   Author = {Litvinenko, VN and Madey, JM and Benson, SV and Burnham, B and Wu,
             Y},
   Title = {Duke storage ring FEL program (Invited Paper)},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {1552},
   Pages = {2-6},
   Year = {1991},
   Abstract = {The Duke storage ring driven FEL scientific program is
             reviewed. The lattice design for Duke storage ring is
             described. The previous design of Duke storage ring is
             similar to the design of 1.2 GeV damping ring for the
             Standard Linear Collider and had the same problem with
             cross- over saturation of the arc magnets. SLAC solved the
             problem by removing the dimples and noses that created fixed
             sextupole moments and installing permanent magnet
             sextupoles. However, this method is very inconvenient for
             the storage rings with energy ramping where variable
             sextupoles are required. A new design for the Duke storage
             ring using existing hardware has allowed us to solve these
             problems.},
   Key = {fds304632}
}


%% Other   
@misc{fds17607,
   Author = {Y. Wu and S. Mikhailov and C. Howell and M. Busch and the HIGS
             development team},
   Title = {The Upgrade of the High Intensity Gamma-ray Source
             (Technical Design Report, 1st version)},
   Year = {2003},
   Month = {August},
   Key = {fds17607}
}