Simulation study of a photo-injector for brightness improvement in Thomson scattering X-ray source via ballistic bunching  

作　　者：丁云泽 杜应超 张振 黄文会 

机构地区：[1]Department of Engineering Physics, Tsinghua University [2]Key Laboratory of Particle & Radiation Imaging (Tsinghua University),Ministry of Education

出　　处：《Chinese Physics C》2014年第2期75-81,共7页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(11127507,11375097,11375098);National Basic Research Program of China(973 Program)(2011CB808302)

摘　　要：Increasing the peak brightness is beneficial to various applications of the Thomson scattering X-ray source. A higher peak brightness of the scattered X-ray pulse demands a shorter scattering electron beam realized by beam compression in the electron beam-line. In this article, we study the possibility of compressing the electron beam in a typical S-band normal conducting photo-injector via ballistic bunching, through just adding a short RF linac section right behind the RF gun, so as to improve the peak brightness of the scattered x-ray pulse. Numerical optimization by ASTRA demonstrates that the peak current can increase from 50 A to 300 A for a 500 pC, 10 ps FWHM electron pulse, while normalized transverse RMS emittance and RMS energy spread increases very little. Correspondingly, the peak brightness of the Thomson scattering X-ray source is estimated to increase about three times.Increasing the peak brightness is beneficial to various applications of the Thomson scattering X-ray source. A higher peak brightness of the scattered X-ray pulse demands a shorter scattering electron beam realized by beam compression in the electron beam-line. In this article, we study the possibility of compressing the electron beam in a typical S-band normal conducting photo-injector via ballistic bunching, through just adding a short RF linac section right behind the RF gun, so as to improve the peak brightness of the scattered x-ray pulse. Numerical optimization by ASTRA demonstrates that the peak current can increase from 50 A to 300 A for a 500 pC, 10 ps FWHM electron pulse, while normalized transverse RMS emittance and RMS energy spread increases very little. Correspondingly, the peak brightness of the Thomson scattering X-ray source is estimated to increase about three times.

关 键 词：beam compression ballistic bunching Thomson scattering X-ray source 

分 类 号：O434.1[机械工程—光学工程]