基于激光康普顿散射的电子束参数测量方法  

The method of measuring electron beam parameters based on laser Compton scattering

作　　者：王振伟 许杭华 郝子锐 张岳 刘龙祥 范功涛 王宏伟 WANG Zhenwei;XU Hanghua;HAO Zirui;ZHANG Yue;LIU Longxiang;FAN Gongtao;WANG Hongwei(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院上海高等研究院,上海201210 [3]中国科学院大学,北京100049

出　　处：《核技术》2024年第11期41-49,共9页Nuclear Techniques

基　　金：科技部重点研发计划(No.2022YFA1602400,No.2023YFA1606901);国家自然科学基金(No.12275338,No.12005280);核数据重点实验室基金(No.JCKY2022201C152)资助。

摘　　要：加速器电子束参数的无损间接测量是一个难题,储存环上传统的X射线针孔成像(X-ray Pinhole Imaging)方法和直线加速器上的狭缝衍射法(Optical Diffraction Radiation,ODR)都存在不足之处。激光康普顿散射(Laser Compton Scattering,LCS)装置是利用相对论电子与低能光子相互碰撞产生高能γ束的新光源。本文提出了一种基于激光康普顿散射光源测量能谱提取电子束参数的方法,该研究旨在通过自主开发的基于Geant4的蒙特卡罗程序模拟重建出与实验测量能谱符合一致的模拟谱,从而获得电子束参数,包括水平方向束斑尺寸、电子能量和发射度。在对上海同步辐射装置(Shanghai Synchrotron Radiation Facility,SSRF)的激光γ光束线站(Shanghai Laser Electron Gamma Source,SLEGS)上的多碰撞角度γ测量能谱做了一致性的验证,结果表明:提取的上海光源储存环电子束参数与理论值符合得较好。这证明了激光康普顿散射是一个有效的电子束参数无损间接测量方法,为后续其他电子束的提取奠定基础。[Background]The non-destructive indirect measurement of accelerator electron beam parameters is a challenging task.Both the traditional X-ray pinhole imaging methods on storage rings and optical diffraction radiation(ODR)from a slit techniques on linear accelerators have their shortcomings.The laser Compton scattering(LCS)device is a new light source that uses relativistic electrons and low-energy photons to collide with each other to produce high-energyγbeams.[Purpose]This study aims to extract the SSRF(Shanghai Synchrotron Radiation Facility)electron beam parameters based on the laser Compton scattering(LCS)techniques.[Method]Under the condition of controllable laser parameters,the electron beam parameters of LCS could be determined by theγbeam measurement.Firstly,simulation spectra reconstructed by self-developed Monte Carlo program based on Geant4 were selected by those best matched with the experimentally measured energy spectra.Then,the corresponding parameters of electron beam,including beam spot size in horizontal direction,electron energy and emittance,were extracted.Finally,the consistency of the gamma energy spectra at different colliding angles measured on the Shanghai Laser Electron Gamma Source(SLEGS)beamline station of SSRF was verified.[Results]The extracted electron beam parameters of the SSRF storing ring are in good agreement with the theoretical values.The electron beam energy at SSRF storage ring BL03SSID interaction point is(3511.44±0.11)MeV,the transverse(horizontal)dimension of the electron beam is(316.60±0.15)μm,and the emittance of the electron beam is(4.56±0.01)nm·rad,with relative deviations of 0.33%,1.6%,8.1%,respectively.[Conclusion]Results of this study demonstrate that LCS is an effective and non-destructive way to determine the electron beam parameters indirectly and lays a stable foundation for the extraction of other parameters of the electron beam.

关 键 词：激光康普顿散射 电子束参数 蒙特卡罗模拟 Γ能谱 

分 类 号：O571.1[理学—粒子物理与原子核物理] TL506[理学—物理]