%% Papers Published
@article{fds153246,
Author = {S. F. Mikhailov and V. G. Popov and S. Huang and J. Li and Y. K.
Wu},
Title = {A Pass-by-pass Gain Measurement Technique for Oscillator
FELs},
Journal = {Proceedings of FEL2008, Gyeongju, Korea,
2008},
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 = {fds153246}
}
@article{fds153247,
Author = {S. Huang and G. Swift and Y. K. Wu},
Title = {Controlling Wiggler Harmonic Radiation to Reduce Damage to
FEL Cavity Mirrors},
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 = {fds153247}
}
@article{fds153248,
Author = {M. A. Blackston and M. W. Ahmed and B. A. Perdue and H. R. Welller and B. Bewer and R. E. Pywell and W. A. Wurtz and R. Igarashi and S.
Kucuker, B. Norum and K. Wang and J. Li and S. F. Mikhailov and V. G.
Popov and Y. K. Wu and B. D. Sawatzky},
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 = {Phys. Rev. C},
Volume = {78},
Number = {034003},
Year = {2008},
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.},
Key = {fds153248}
}
@article{fds148786,
Author = {H.R. Weller and M.W. Ahmed and H. Gao and W. Tornow and Y.K. Wu and M. Gai and R. Miskimen},
Title = {Research Opportunities at the Upgraded HIγS},
Journal = {Progress in Particle and Nuclear Physics (2008),
doi:10.1016/j.ppnp.2008.07.001},
Year = {2008},
Abstract = {The High Intensity Gamma-ray Source (HIGS) 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 gamma-ray beams. An
upgrade which allows for the production of - gamma-rays up
to energies of about 150 MeV having total intensities in
excess of 108/sec 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 doublepolarization 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
spinpolarizabilities of the proton and the neutron. Studies
at pion-threshold designed to test the predictions of Chiral
Perturbation Theory and to observe Isospin-symmetry breaking
effects are also being planned. 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.},
Key = {fds148786}
}
@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{fds141064,
Author = {S. M. Hartman and S. F. Mikhailov and V. Popov and Y. K.
Wu},
Title = {A Physics Based Approach for Ramping Magnet Control in a
Compact Booster},
Pages = {515-517},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141064}
}
@article{fds141065,
Author = {Y. K. Wu and J. Li and V. Popov and S. F. Mikhailov and P.
Wang},
Title = {A Tune Measurement System for Low Current and Energy Ramping
Operation of a Booster Synchrotron},
Pages = {4063-4065},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141065}
}
@article{fds141066,
Author = {Y. K. Wu},
Title = {Accelerator Physics Research and Light Source Development
Programs at Duke University},
Pages = {1215-1217},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141066}
}
@article{fds141041,
Author = {C. Sun and Y. K. Wu},
Title = {The Feasibility Study of Measuring the Polarization of a
Relativistic Electron Beam Using a Compton Scattering
Gamma-Ray Source},
Pages = {4057-4059},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141041}
}
@article{fds141042,
Author = {V. Popov and M. D. Busch and S. M. Hartman and J. Li and S. F.
Mikhailov and P. W. Wallace and P. Wang and Y. K. Wu and G. Y.
Kurkin},
Title = {Electron Beam Diagnostics for Compact 1.2 GeV Booster
Synchrotron},
Pages = {4051-4053},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141042}
}
@article{fds141043,
Author = {S. Huang and J. Li and Y. K. Wu},
Title = {A Direct Electron Beam Energy Spread Measurement System for
Beam Instability and FEL Research},
Pages = {4045-4047},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141043}
}
@article{fds141044,
Author = {J. Li and P. Wang and Y. K. Wu},
Title = {BPM signal conditioning for a wide range of single bunch
current operation in Duke storage ring},
Pages = {4042-4044},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141044}
}
@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{fds141046,
Author = {J. Li and S. Huang and S. F. Mikhailov and V. Popov and Y. K.
Wu},
Title = {Compensation of the Beam Dynamics Effects Caused by the
Extraction Lambertson Septum of the HIGS
Booster},
Pages = {3582-3584},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141046}
}
@article{fds141060,
Author = {S. F. Mikhailov and O. Anchugov and N. Gavrilov and G. Y. Kurkin and Yu.
Matveev, D. Shvedov and N. Vinokurov and M. D. Busch and M. Emamian and S. M. Hartman and Y. Kim and J. Li and V. Popov and G. Swift and P. W.
Wallace and P. Wang and Y. K. Wu and C. R. Howell},
Title = {Commissioning of the Booster Injector Synchrotron for the
HIGS Facility at Duke University},
Pages = {1209-1211},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141060}
}
@article{fds141061,
Author = {S. F. Mikhailov and S. M. Hartman and J. Li and V. Popov and Y. K.
Wu},
Title = {Challenges for the Energy Ramping in a Compact Booster
Synchrotron},
Pages = {1212-1214},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141061}
}
@article{fds141062,
Author = {V. Popov and M. D. Busch and S. M. Hartman and S. F. Mikhailov and O.
Oakeley, P. W. Wallace and Y. K. Wu},
Title = {Power Supply System for a Compact 1.2 GeV Booster
Synchrotron},
Pages = {521-523},
Booktitle = {Proceedings of 2007 Particle Accelerator
Conference},
Year = {2007},
Key = {fds141062}
}
@article{fds52598,
Author = {Y. K. Wu and N. A. Vinokurov and S. Mikhailov and J. Li and V.
Popov},
Title = {High-Gain Lasing and Polarization Switch with a Distributed
Optical-Klystron Free-Electron Laser},
Journal = {Phys. Rev. Lett.},
Volume = {96},
Number = {224801},
Year = {2006},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000096000022224801000001&idtype=cvips&gifs=yes},
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.},
Key = {fds52598}
}
@article{fds52600,
Author = {V.Werner, N.Pietralla and P.von Brentano and U.Kneissl, H.H.Pitz and A.Tonchev, M.W.Ahmed and C.Fransen, H.von Garrel and C.Kohstall, J.Li and A.Linnemann, S.Muller and I.V.Pinayev, D.Savran and M.Scheck, F.Stedile and W.Tornow, S.Walter and H.R.Weller, Y.K.Wu},
Title = {New findings for mixed-symmetry states},
Volume = {819},
Pages = {340-344},
Booktitle = {AIP Conf.Proc.},
Editor = {A.Woehr, A.Aprahamian},
Year = {2006},
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.},
Key = {fds52600}
}
@article{fds52599,
Author = {T. C. Li and N. Pietralla and A. P. Tonchev and M. W. Ahmed and T. Ahn and C. Angell and M. Blackston and A. Costin and K. Keeter and J. Li and A.
Lisetskiy, Y. Parpottas and B. Perdue and G. Rainovski and W. Tornow and H. R. Weller and Y. K. Wu},
Title = {First evidence for spin-flip M1 strength in
Ar40},
Journal = {Physical Review C},
Volume = {73},
Number = {054306},
Year = {2006},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000073000005054306000001&idtype=cvips&gifs=yes},
Abstract = {The 40Ar(gamma-->,gamma[prime]) photon scattering reaction
was used to search for spin-flip M1 strength in 40Ar. The
nearly monochromatic, linearly polarized photon beam of
HIgammaS, 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
40Ar.},
Key = {fds52599}
}
@article{fds43903,
Author = {Y. K. Wu and S. Mikhailov and J. Li and V. Popov and N. A. Vinokurov and N.
G. Gavrilov and O. A. Shevchenko and P. D. Vobly and G. N.
Kulipanov},
Title = {First Lasing and Initial Operation of a Circularly Polarized
Optical Klystron OK-5 FEL and a Variably Polarized
Distributed Optical Klystron DOK-1 FEL at
Duke},
Journal = {Proceedings of FEL2005, Stanford, CA, 2005},
Year = {2005},
Month = {August},
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 = {fds43903}
}
@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},
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},
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{fds43926,
Author = {V. Popov and S.M. Hartman and S. Mikhailov and O. Oakeley and P.W.
Wallace, Y.K. Wu},
Title = {3 kA Power Supplies for the Duke OK-5 FEL
Wigglers},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
Month = {May},
Abstract = {The next generation electromagnetic OK-5/Duke storage ring
FEL wigglers require three 3kA/70V power supplies with
current stability about 20 ppm and current ripples less than
20ppm in their full operating range. Duke FEL Laboratory
acquired three out-of-service thyristor controllable power
supplies (Transrex, 5kA/100V) which was built almost 30
years ago. The existing archaic firing circuit, lack of any
output voltage filtering and outdated DCCT, would not be
able to meet the above requirements.To deliver the desirable
high performance with very limited funds, all three T-Rex
power supplies have been completely rebuilt in house at
DFELL. Modern high stability electronic components and a
Danfysik DCCT with a high current stability have been used.
New symmetrical firing circuit, efficient passive LC filter
and reliable transformer-coupled active filter are used to
reduce output current ripples to an appropriate level. At
the present time, the first refurbished power supply in
operation since August, 2004 with good overall performance.
The power supply testing results of this unit will also be
presented in this paper.},
Key = {fds43926}
}
@article{fds43927,
Author = {V. Popov and S.M. Hartman and S. Mikhailov and O. Oakeley and P.W.
Wallace, Y.K. Wu},
Title = {Trim Power Supplies for the Duke Booster and Storage
Ring},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
Month = {May},
Abstract = {The on-going Duke storage ring upgrades and the development
of a new booster synchrotron injection require more than 100
units of high performance unipolar and bipolar trim power
supplies in the current range of -15A to +15A. 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 is then 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 (0-12A) 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
their performance results of both unipolar and bipolar
supplies will be presented in this paper.},
Key = {fds43927}
}
@article{fds43929,
Author = {J. Li and C. Sun and Y.K. Wu},
Title = {Improved Long Radius of Curvature Measurement System for FEL
Mirrors},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
Month = {May},
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 DFELL for years. Recently, we have
significantly upgraded this measurement apparatus by
utilizing a HeNe 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.},
Key = {fds43929}
}
@article{fds43932,
Author = {S. Mikhailov and M.D. Busch and M. Emamian and J.F. Faircloth and S.M.
Hartman, J. Li and V. Popov and G. Swift and V. Vylet and P.W. Wallace and P. Wang and Y.K. Wu and O. Anchugov and N. Gavrilov and G.Y. Kurkin and Yu.
Matveev, D. Shvedov and N. Vinokurov},
Title = {Status of the Booster Injector for the Duke FEL Storage
Ring},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
Month = {May},
Abstract = {This paper presents the current status of the booster
synchrotron for the Duke FEL 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
Duke FEL 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 fabricated in the Budker Institute of Nuclear
Physics, Russia. The diagnostic and control system is being
developed in the FEL lab, Duke University. The commissioning
of the booster synchrotron is planned for fall
2005.},
Key = {fds43932}
}
@article{fds35155,
Author = {Y. K. Wu and J. Li and J. Wu},
Title = {Anomalous Hollow Electron Beams in a Storage
Ring},
Journal = {Physical Review Letter},
Volume = {94},
Number = {134802},
Year = {2005},
Month = {April},
url = {http://link.aps.org/abstract/PRL/v94/e134802},
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.},
Key = {fds35155}
}
@article{fds35156,
Author = {J. Feng and E. Forest and A.A. MacDowell and M. Marcus and H. Padmore and S. Raoux and D. Robin and A. Scholl and R. Schlueter and P. Schmid and J.
Stöhr, W. Wan and D.H. Wei and Y. Wu},
Title = {An X-ray Photoemission Electron Microscope Using Electron
Mirror Aberration Corrector for the Study of Complex
Materials},
Journal = {Journal of Physics: Condensed Matter},
Volume = {17},
Pages = {S1339-S1350},
Year = {2005},
Month = {April},
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.},
Key = {fds35156}
}
@article{fds35157,
Author = {D. Savran and S. Mueller and A. Zilges and M. Babilon and M.W. Ahmed and J.H. Kelley and A. Tonchev and W. Tornow and H.R. Weller and J. Li and I. V. Pinayev and Y. K. Wu and N. Pietralla},
Title = {Parity assignments in 172,174Yb using polarized photons and
the K quantum number in rare earth nuclei},
Journal = {Physical Review C},
Volume = {71},
Number = {034304},
Year = {2005},
Month = {March},
url = {http://link.aps.org/abstract/PRC/v71/e034304},
Abstract = {The 100% polarized photon beam at the high intensity gamma
ray source (HIgammaS) 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 (gamma-->,gamma') 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 gamma-decay
branching ratios and parity quantum numbers is given for the
rare earth nuclei.},
Key = {fds35157}
}
@article{fds30979,
Author = {Peter Schmid and Jun Feng and Howard Padmore and David Robin and Harald
Rose, Ross Schlueter and Weishi Wan and Etienne Forest and Ying
Wu},
Title = {Correction and alignment strategies for the beam separator
of the photoemission electron microscope 3
(PEEM3)},
Journal = {Rev. Sci. Instrum.},
Volume = {76},
Number = {2},
Year = {2005},
Month = {February},
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.},
Key = {fds30979}
}
@article{fds43928,
Author = {C. Steier and D. Robin and W. Decking and J. Laskar and L.S.N. Nadolski and Y.K. Wu},
Title = {Measuring and Understanding the Momentum Aperture in a
Storage Ring},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
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 turn-by-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.},
Key = {fds43928}
}
@article{fds43930,
Author = {G.Y. Kurkin and S.M. Hartman and S. Mikhailov and Y.K. Wu and I.P.
Pinayev},
Title = {A New Timing System for the Duke Booster and Storage
Ring},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
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.},
Key = {fds43930}
}
@article{fds43931,
Author = {S.M. Hartman and S. Mikhailov and Y.K. Wu},
Title = {A Control System for the Duke Booster Synchrotron},
Journal = {Proceedings of 2005 Particle Accelerator Conference,
Knoxville, Tennessee},
Year = {2005},
Abstract = {The Duke FEL 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 Duke storage
ring.},
Key = {fds43931}
}
@article{fds43875,
Author = {A. P. Tonchev and M. Boswell and C. R. Howell and H. J. Karwowski and J.
H. Kelley and W. Tornow and Y. K. Wu},
Title = {The high intensity gamma-ray source HIGS and recent
measurements},
Journal = {Nucl. Instr. Methods B.},
Volume = {241},
Pages = {170-175},
Year = {2005},
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 105–5 × 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.},
Key = {fds43875}
}
@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{fds30229,
Author = {C. Fransen and N. Pietralla and A. P. Tonchev and M. W. Ahmed and J.
Chen, G. Feldman and U. Kneissl and J. Li and V. N. Litvinenko and B.
Perdue, I. V. Pinayev and H. H. Pitz and R. Prior and K. Sabourov and M.
Spraker, W. Tornow and H. R. Weller and V. Werner and Y. K. Wu and S. W. Yates},
Title = {Parity assignments to strong dipole excitations of 92Zr and
96Mo},
Journal = {Physical Review C},
Number = {70},
Pages = {044317},
Year = {2004},
Month = {October},
url = {http://link.aps.org/abstract/PRC/v70/e044317},
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.},
Key = {fds30229}
}
@article{fds43876,
Author = {J. Feng and A. A. MacDowell and R. Duarte and A. Doran and E. Forest and N.
Kelez, M. Marcus and D. Dunson and H. Padmore and K. Petermann and S.
Raoux, D. Robin and A. Scholl and R. Schlueter and P. Schmid and W. Wan and D. H. Wei and Y. Wu},
Title = {An aberration corrected photoemission electron microscope at
the advanced light source},
Journal = {AIP conference proceedings},
Volume = {705},
Pages = {1070},
Editor = {T.Warwick, J.Arthur and H.PAdmore, J.Stohr},
Year = {2004},
Key = {fds43876}
}
@article{fds30226,
Author = {Y.K. Wu and D.S. Robin and E. Forest and R. Schlueter and S. Anders and J.
Feng, H. Padmore and D.H. Wei},
Title = {Design and analysis of beam separator magnets for third
generation aberration compensated PEEMs},
Journal = {Nuclear Instruments and Methods in Physics Research
A},
Volume = {519},
Pages = {230-241},
Year = {2004},
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 ux
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.},
Key = {fds30226}
}
@article{fds17528,
Author = {C. Steier and E. Forest and L. Nadolski and H. Nishimura and D. Robin and W. Wan and Y. Wu and A. Zholents},
Title = {ACCELERATOR PHYSICS CHALLENGES OF THE FS-SLICING UPGRADE AT
THE ALS},
Journal = {Proceedings of PAC2003},
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 repition 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 (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 = {fds17528}
}
@article{fds17530,
Author = {Weishi Wan and Hiroshi Nishimura and David Robin and Christoph
Steier, Ying Wu and Etienne Forest},
Title = {ID MODELING AT THE ALS},
Journal = {Proceedings of PAC2003},
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 = {fds17530}
}
@article{fds17531,
Author = {S.Mikhailov, V.Litvinenko and M. Busch and M. Emamian and S.Hartman, I.Pinayev and V.Popov, G.Swift and P.Wallace, Y.Wu and N.Gavrilov, Yu. Matveev and D.Shvedov, N.Vinokurov and P.Vobly},
Title = {STATUS OF THE BOOSTER SYNCHROTRON FOR DUKE FEL STORAGE
RING},
Journal = {Proceedings of PAC2003},
Year = {2003},
Month = {Winter},
Abstract = {In this paper we present current status of the Booster
Synchrotron for the Duke FEL storage ring. The Booster will
provide full energy injection into the storage ring at
energy from 0.25 to 1.2 GeV. The Duke storage ring FEL (SR
FEL) operates in lasing mode with 193-700 nm wavelength
range. This range will be extended into VUV in near future.
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 -rays from 2
MeV to about 200 MeV (currently from 2 MeV to 58 MeV).
Generation of -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 Booster has a
robust FODO lattice. The paper presents the design of the
magnetic elements and their 3D simulations using MERMAID 3D
code. We also present design and parameters of fast
extraction kicker with 10 nS pulse duration. The elements of
the magnetic system, vacuum system, injection and extraction
kickers will be designed and fabricated by Budker Institute
of Nuclear Physics, Novosibirsk, Russia.},
Key = {fds17531}
}
@article{fds17533,
Author = {Y. K. Wu and J. Li and S. F. Mikhailov and V. Litvinenko},
Title = {NONLINEAR DYNAMICS IN THE DUKE STORAGE RING WITH FEL
WIGGLERS},
Journal = {Proceedings of PAC2003},
Year = {2003},
Month = {Winter},
Abstract = {Single particle beam dynamics in the storage ring can be
significantly influenced by long and strong field insertion
devices, such as FEL wigglers in the light source ring and
damping wigglers in the next generation damping ring. An
explicit symplectic integrator for arbitrary wiggler field
has been developed and used for detailed beam dynamics
studies for storage rings with wigglers. A proper dynamics
model is critical for uncovering the details of the stable
phase space region with varying diffusion rates computed
from the particle tracking data using the frequency analysis
technique NAFF. We focus our studies on the influence of a
24m long variably polarized OK-5 FEL system to be installed
in the Duke storage ring in 2003. Particle tracking
simulations are performed for various operation modes of the
FEL wigglers. Lattice parameters are then adjusted
accordingly to optimize the dynamic aperture for a
particular mode of FEL operation.},
Key = {fds17533}
}
@article{fds17534,
Author = {Y. K. Wu and V. G. Popov and S. Hartman and I. Pinayev and S. F.
Mikhailov and P. Morcombe and O. Oakeley and P. Wallace and P. Wang and V.
Litvinenko},
Title = {IMPROVING POWER SUPPLY PERFORMANCE FOR THE DUKE STORAGE
RING},
Journal = {Proceedings of PAC2003},
Year = {2003},
Month = {Winter},
Abstract = {One of the major tasks of the recent Duke storage ring
upgrade was the improvement of magnet power supply
performance. Prior to the upgrade, sixty-four small DC power
supplies acquired in the mid 1980's were used to
individually power all quadrupoles. Because of the marginal
performance of these power supplies, we were not able to
establish stable and reliable operation of the storage ring.
The ring upgrade allowed us to replace all of these power
supplies with modern ones. In the arc, all quadrupoles are
connected in series to form magnet families powered by four
larger power supplies. In the straight sections, we power
paired quadrupoles in series or individually with new power
supplies. For each of these new power supplies and for the
other existing major power supplies, we performed detailed
DC testing, AC noise measurements and transition response
measurements. Most power supplies required in-house
modifications to achieve our specifications. In this paper,
we describe and report the results of the magnet power
supply testing program for the Duke storage ring
upgrade.},
Key = {fds17534}
}
@article{fds17536,
Author = {J. Li and Y.K. Wu and S. Hartman},
Title = {POWER SUPPLY PERFORMANCE MONITORING AND ANALYSIS USING
OPERATION DATA},
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 kinds of DC power supplies in Duke FEL
Storage ring. The performance data of power supplies can be
collected in an 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
locate a power supply with degraded performance and perform
preventative maintenance.},
Key = {fds17536}
}
@article{fds17537,
Author = {Y. K. Wu and J. Li and P. Wang and V. Litvinenko},
Title = {BPM AND ORBIT CORRECTION SYSTEMS AT THE DUKE STORAGE
RING},
Journal = {Proceedings of PAC2003},
Year = {2003},
Month = {Winter},
Abstract = {The closed orbit measurement system at the Duke storage ring
is comprised of 34 Bergoz beam position monitors (BPMs). To
accommodate many different operation modes of the storage
ring, the BPM system needs to be tailored to work with a
wide range of signal levels. In the first part of the paper,
we report the recent work on improving the performance of
the BPM system for a variety of beam conditions. The second
part of the paper focuses on the closed orbit correction and
feedback systems on the Duke storage ring, including local
orbit bumps for insertion devices and end-of-arc orbit
compensation, a global orbit correction system, and a slow
orbit feedback system. We report the measurements and
performance of the orbit orrection and feedback
system.},
Key = {fds17537}
}
@article{fds17526,
Author = {Y. K. Wu and E. Forest and D. S. Robin},
Title = {Explicit symplectic integrator for s-dependent static
magnetic field},
Journal = {Physical Review E},
Number = {68},
Pages = {046502},
Publisher = {The American Physical Society},
Year = {2003},
Month = {October},
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 = {fds17526}
}
@article{fds17529,
Author = {Y. K. Wu and S. Hartman and S. F. Mikhailov},
Title = {A PHYSICS BASED CONTROL SYSTEM FOR THE DUKE STORAGE
RING},
Journal = {Proceedings of PAC2003},
Year = {2003},
Month = {Fall},
Abstract = {At the Duke FEL Lab, we have developed and implemented a new
storage ring control system based upon physical quantities.
Most other operational accelerator control systems are base
on direct controls of various hardware systems, e.g. setting
a power supply current to control a magnet. Such systems
present a raw interface to a very complex accelerator and
need to be supplemented by a high level physics control to
perform sophisticated operations. The new control system at
Duke uses an integrated approach to optimize the overall
system performance, moving many critical high level
functions to the low level realtime system. This system is
designed around physical quantities experienced by the beam,
e.g. magnetic multipole strengths such as the bending angle,
normalized focusing strength (K1), and sextupole strength
(K2), all based upon measured magnetic field data. With this
system, energy ramping and transition between different
operation modes becomes a trivial task. It also allows us to
focus on developing high level controls regardless of the
beam energy. Furthermore, with better understanding of the
storage ring, we can fine tune our control in the low level
to present an invariant virtual machine to the operator,
independent of the beam energy.},
Key = {fds17529}
}
@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{fds4254,
Author = {J. Feng and H. Padmore and D. H. Wei and S. Anders and Y. Wu and A. Scholl and D. Robin},
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},
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.},
Key = {fds4254}
}
@article{fds4251,
Author = {Y. Wu and H. Nishimura and D. S. Robin and A. A. Zholents and E.
Fores},
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},
Volume = {481},
Pages = {675-681},
Year = {2002},
Month = {September},
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 = {fds4251}
}
@article{fds4253,
Author = {C. Steier and D. Robin and L. Nadolski and W. Decking and Y. Wu and J.
Laskar},
Title = {Measuring and optimizing the momentum aperture in a particle
accelerator},
Journal = {Phys. Rev. E},
Volume = {65},
Number = {056506},
Year = {2002},
Month = {May},
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.},
Key = {fds4253}
}
@article{fds4243,
Author = {S. F. Mikhailov and V. N. Litvinenko and Y.
Wu},
Title = {Low emittance lattice for the Duke storage ring soft X-ray
FEL},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Volume = {475},
Pages = {417-424},
Year = {2001},
Month = {December},
Abstract = {In this paper, we present a possible lattice for the Duke
storage ring with horizontal emittance of 1.4 nm 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 18 nm 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.},
Key = {fds4243}
}
@article{fds4244,
Author = {V. N. Litvinenko and S. F. Mikhailov and O. A. Shevchenko and N. A.
Vinokurov and N. G. Gavrilov and G. N. Kulipanov and T. V. Shaftan and P. D. Vobly and Y. Wu},
Title = {The OK-5/Duke storage ring VUV FEL with variable
polarization},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Volume = {475},
Pages = {407-416},
Year = {2001},
Month = {December},
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.},
Key = {fds4244}
}
@article{fds4245,
Author = {Y. Wu and V. N. Litvinenko and S. F. Mikhailov and O. A. Shevchenko and N. A. Vinokurov and N. G. Gavrilov and T. V. Shaftan and D. A.
Kairan},
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},
Volume = {475},
Pages = {253-259},
Year = {2001},
Month = {December},
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.},
Key = {fds4245}
}
@article{fds4246,
Author = {V. N. Litvinenko and S. H. Park and I. V. Pinayev and Y.
Wu},
Title = {Time structure of the OK-4/Duke storage ring
FEL},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Year = {2001},
Month = {December},
Abstract = {n 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 1.2 ps
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.},
Key = {fds4246}
}
@article{fds4247,
Author = {V. N. Litvinenko and S. H. Park and I. V. Pinayev and Y. Wu and A.
Lumpkin and B. Yang},
Title = {Fourier limited micro-pulses in the OK-4/Duke storage ring
FEL},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Volume = {475},
Pages = {234-239},
Year = {2001},
Month = {December},
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 193.7 nm to 730
nm, 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 1.3 ps 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.},
Key = {fds4247}
}
@article{fds4248,
Author = {Igor V. Pinayev and Vladimir N. Litvinenko and Seong Hee Park and Ying Wu and Mark Emamian and Nelson Hower and Janet Patterson and Gary Swift},
Title = {Giant high-peak power pulses in the UV OK-4/Duke storage
ring FEL using the gain modulator},
Volume = {475},
Pages = {222-228},
Year = {2001},
Month = {December},
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.},
Key = {fds4248}
}
@article{fds4249,
Author = {Vladimir N. Litvinenko and Seong Hee Park and Igor V. Pinayev and Ying Wu},
Title = {peration of the OK-4/Duke storage ring FEL below 200
nm},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Volume = {475},
Pages = {195-204},
Year = {2001},
Month = {December},
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.},
Key = {fds4249}
}
@article{fds4250,
Author = {V. N. Litvinenko and S. H. Park and I. V. Pinayev and Y.
Wu},
Title = {Power limitations in the OK-4/Duke storage ring
FEL},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Volume = {475},
Pages = {65-73},
Year = {2001},
Month = {December},
Abstract = {n 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 730 nm using electron beam energies from 220
to 800 MeV. 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.},
Key = {fds4250}
}
@article{fds4255,
Author = {Y. Wu and E. Forest and D. S. Robin and H. Nishimura and A.
Wolski},
Title = {SYMPLECTIC MODELS FOR GENERAL INSERTION DEVICES},
Pages = {459-461},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
Abstract = {A variety of insertion devices (IDs), wigglers and
undu-lators, 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 pro-posed as the main source of radiation damping at
next gen-eration 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 sym-plectic 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 wig-gler harmonics and arbitrary
polarizations.},
Key = {fds4255}
}
@article{fds4256,
Author = {S. Hartman and V. N. Litvinenko and G. Swift and I. Pinayev and Y.
Wu},
Title = {Control System Design and Upgrade Considerationsfor the Duke
Free Electron Laser Laboratory},
Pages = {785-787},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicag},
Year = {2001},
Month = {June},
Abstract = {The Duke Free Electron Laser Laboratory currently op-erates
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 Indus-trial 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 = {fds4256}
}
@article{fds4257,
Author = {V.N.Litvinenko, O.A.Shevchenko and S.F.Mikhailov, Y.
Wu},
Title = {PROJECT FOR GENERATION OF FEMTOSECOND X-RAY BEAMS FROMTHE
DUKE STORAGE RING},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
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 10 12 to 10 13
ph/sec, and the average spectral brightness up to 0.5 . 10
15 ph/sec/mm 2 /mrad 2 /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 = {fds4257}
}
@article{fds4258,
Author = {O.A. Shevchenko and V.N. Litvinenko and S.M. Mikhailov and N.A.
Vinokurov, N.G. Gavrilov and P.D. Vobly and Y.
Wu},
Title = {THE VUV/UV OK-5 DUKE STORAGE RING FEL WITH VARIABLE
POLARIZATION},
Pages = {2833-2835},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
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 = {fds4258}
}
@article{fds4259,
Author = {S.F.Mikhailov, V.N.Litvinenko and Y.Wu},
Title = {LOW EMITTANCE LATTICES FOR THE DUKE FEL STORAGE
RING},
Pages = {3528-3530},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
Abstract = {In this paper we present two options for a new lattice of
the 1 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 = {fds4259}
}
@article{fds4260,
Author = {C. Steier and A. Biocca and E. Domning and S. Jacobson and G. Portmann and Y. Wu},
Title = {DESIGN OF A FAST GLOBAL ORBIT FEEDBACK SYSTEM FOR THE
ADVANCED LIGHT SOURCE},
Pages = {1252-1254},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
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
with-out 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 stabil-ity further. Moreover, the expansion of
the capabilities of the ALS creates new sources of closed
orbit noise. There-fore 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 up-date 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 sys-tem design, measurements of transfer
functions and tests with small prototype systems will be
presented.},
Key = {fds4260}
}
@article{fds4261,
Author = {C. Steier and D. Robin and Y. Wu and W. Decking and J. Laskar and L.
Nadolski},
Title = {UNDERSTANDING THE DYNAMIC MOMENTUM APERTURE OF THE ADVANCED
LIGHT SOURCE },
Pages = {434-436},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
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 momen-tum aperture. At the ALS
the size of the momentum ac-ceptance 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 re-gions 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 = {fds4261}
}
@article{fds4262,
Author = {W. Barry and A. Biocca and J. M. Byrd and W. Byrne and S. Kwiatkowski and M. C. Martin and W. R. McKinney and H. Nishimura and F. Sannibale and C.
Steier, K. Rex and D. Robin and G. Stover and W. Thur and Y.
Wu},
Title = {A DEDICATED INFRARED SYNCHROTRON RADIATION SOURCE AT THE
ALS},
Pages = {2623-2635},
Booktitle = {Proceedings of the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
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 = {fds4262}
}
@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{fds4264,
Author = {A. Wolski and Y. Wu},
Title = {EFFECTS OF DAMPING WIGGLERS ON BEAM DYNAMICS IN THE NLC
DAMPING RINGS},
Pages = {3798-3800},
Booktitle = {EFFECTS OF DAMPING WIGGLERS ON BEAM DYNAMICS Proceedings of
the 2001 Particle Accelerator Conference,
Chicago},
Year = {2001},
Month = {June},
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 T 2 m [1]. 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 [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 = {fds4264}
}
@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{fds4252,
Author = {E. C. Schreiber and R. S. Canon and B. T. Crowley and C. R. Howell and J. H. Kelley and V. N. Litvinenko and S. O. Nelson and S. H. Park and I.
V. Pinayev and R. M. Prior and K. Sabouro and M. Spraker and W. Tornow and Y. Wu and E. A. Wulf and H. R. Weller},
Title = {First measurement of the near-threshold 2H(gamma,n)p
analyzing power using a free-electron laser based gamma-ray
source},
Journal = {Phys. Rev. C},
Volume = {61},
Number = {061604},
Year = {2000},
Month = {December},
Abstract = {The first measurement of the 2H(gamma,n)p analyzing power
near threshold has been performed using the High-Intensity
Gamma-ray Source (HIGS) at the Duke Free-Electron Laser
Laboratory. A 3.58 MeV -ray beam having an energy resolution
of 2.5% and 100% linear polarization was incident on an
active C6D12 target. Outgoing neutrons were detected
parallel and perpendicular to the plane of gamma-ray
polarization at a lab angle of 150¡ã. The experimentally
determined analyzing power provides a sensitive measurement
of the relative E1 and M1 contributions to the total cross
section. (C)2000 The American Physical Society},
Key = {fds4252}
}
@article{fds4242,
Author = {V. N. Litvinenko and S. H. Park and I. V. Pinayev and Y.
Wu},
Title = {Performance of the OK-4/Duke storage ring
FEL},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A:},
Volume = {470},
Pages = {66-75},
Year = {1999},
Month = {September},
Abstract = {n 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 -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.},
Key = {fds4242}
}
@article{fds4241,
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 = {OK-4/Duke storage ring FEL lasing in the
deep-UV},
Journal = {Nuclear Instruments and Methods in Physics Research Section
A},
Volume = {429},
Pages = {151-158},
Year = {1999},
Month = {June},
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.},
Key = {fds4241}
}
%% Papers Submitted
@article{fds152988,
Author = {G. Rusev and A. P. Tonchev and W. Tornow and R. Schwengner and C. Sun and Y. K. Wu},
Title = {Multipole mixing ratios of transitions in
$^{11}$B,},
Journal = {Phys. Rev. C,},
Year = {2008},
Key = {fds152988}
}
@article{fds52602,
Author = {V. Werner and N. Pietralla and P. von Brentano and M. W. Ahmed and M.
Babilon, C. Fransen and J. H. Kelley and C. Kohstall and U. Kneissl and J. Li and A. Linnemann and S. Muller and H. H. Pitz and D. Savran and M.
Scheck, F. Stedile and A. Tonchev and W. Tornow and H. von Garrel and S.
Walter, H. R. Weller and Y. K. Wu},
Title = {Evidence for Coupling of the Scissors Mode to
gamma-Vibrations in Rotors},
Journal = {submitted to PRL},
Year = {2006},
Key = {fds52602}
}
%% Other
@article{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}
}