相干渡越辐射束团纵向分布重建方法  

Reconstruction algorithm for bunch longitudinal distribution of coherent transition radiation

作　　者：袁肖肖 李佳 闫文兵 冉朝晖 杨鑫 赵全堂[1,2] 宗阳 曹树春[1,2] 张子民[1,2] Yuan Xiaoxiao;Li Jia;Yan Wenbing;Ran Zhaohui;Yang Xin;Zhao Quantang;Zong Yang;Cao Shuchun;Zhang Zimin(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]中国科学院大学,北京100049

出　　处：《强激光与粒子束》2023年第11期77-84,共8页High Power Laser and Particle Beams

基　　金：国家重点研发计划项目(2019YFA0404900);甘肃省自然科学基金项目(21JR7RA103)。

摘　　要：实验上通过相干渡越辐射(CTR)能谱分析法测量束团长度以及进行纵向束团形状重建已成为一种有效的束流诊断手段。通过迈克尔逊干涉仪测量太赫兹辐射能谱,通常实验所用探测器只能测量辐射的强度谱的幅值,且由于缺少相位无法直接进行束团形状重建。目前重建算法主要有Kramers-Kronig(K-K)相位分析法和代数迭代重建算法。利用这两种算法分别对高斯分布和带拖尾的高斯分布模型进行验证并进行了对比,其中K-K得出的重建结果存在一定的误差,迭代算法在解决重建反转歧义、重建噪声抑制等表现良好。同时利用这两种算法对兰州高能电子成像平台CTR实验结果进行了重建及分析,得出了对应的重建结果,为后续高能电子束成像平台的束流诊断反馈提供了一种参考手段。Coherent transition radiation(CTR)spectroscopy has emerged as a highly productive technique for measuring bunch length and reconstructing longitudinal bunch profiles.However,conventional Michelson interferometry is limited to the amplitude measurement of terahertz radiation spectra,rendering it incapable of directly reconstructing the bunch profile owing to the absence of phase information.Currently,the predominant reconstruction methods encompass the Kramers-Kronig(K-K)phase analysis and algebraic iterative reconstruction algorithms.These two algorithms were employed to validate both Gaussian distribution and Gaussian distribution with tail models,respectively.The outcomes obtained from the K-K algorithm exhibit notable uncertainty,whereas the iterative algorithm showcased superior performance in resolving reconstruction ambiguities and mitigating noise interference.Within the framework of the Lanzhou High Energy Electronic Imaging Platform,a specialized Michelson interferometer was meticulously engineered for the precise measurement of CTR interference spectra.Subsequent to two distinct measurements,the acquired data was subjected to reconstruction and comprehensive analysis employing the aforementioned algorithms.As a result,detailed longitudinal beam cluster reconstructions for the electron beam were successfully obtained.These findings constitute a reference for subsequent beam diagnosis and feedback mechanisms within the High Energy Electron Beam Imaging Platform.

关 键 词：相干渡越辐射 纵向束团重建 重建算法 束流诊断 

分 类 号：TL53[核科学技术—核技术及应用]