Publications [#167639] of Ying Wu

Papers Published
  1. Stepan F. Mikhailov, Jingyi Li, Victor Popov, Ying K. Wu, Pass-by-pass multistage FEL gain measurement technique for a storage ring FEL, Proceedings of 2009 Particle Accelerator Conference (2009), pp. 1241-1243 .

    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.