High-brightness photo-injector with standing-wave buncher-based ballistic bunching scheme for inverse Compton scattering light source  

作　　者：Jian-Xin Wang Kui Zhou Peng Li De-Xin Xiao Li-Jun Shan Xu-Ming Shen Yu Liu Zheng Zhou Han-Bin Wang Dai Wu 

机构地区：[1]Institute of Applied Electronics,China Academy of Engineering Physics,Mianyang 621900,China

出　　处：《Nuclear Science and Techniques》2022年第4期51-61,共11页核技术（英文）

基　　金：supported by National Natural Science Foundation of China(NSFC)(Nos.12005211,11905210,11975218 and 11805192).

摘　　要：We report our recent progress in the design and simulation of a high-brightness S-band photo-injector with a ballistic bunching scheme aimed at driving an inverse Compton scattering(ICS)X-ray source.By adding a short standing-wave buncher between the RF gun and first booster in a conventional S-band photo-injector,electron bunches with a 500 pC charge can be compressed to the sub-picosecond level with very limited input RF power and an unchanged basic layout of the photo-injector.Beam dynamics analysis indicates that fine tuning of the focusing strength of the gun and linac solenoid can well balance additional focusing provided by the standing wave buncher and generate a well-compensated transverse emittance.Thorough bunching dynamics simulations with different operating conditions of the buncher show that a buncher with more cells and a moderate gradient is suitable for simultaneously obtaining a short bunch duration and low emittance.In a typical case of a 9-cell buncher with a 38 MV/m gradient,an ultrashort bunch duration of 0.5 ps(corresponding to a compression ratio of>5)and a low emittance of<1 mm mrad can be readily obtained for a 500 pC electron pulse.This feasible ballistic bunching scheme will facilitate the implementation of an ultrashort pulse mode inverse Compton scattering X-ray source on most existing S-band photo-injectors.

关 键 词：Beam brightness Ballistic bunching Emittance compensation Compton scattering X-ray source 

分 类 号：TL81[核科学技术—核技术及应用]