Transverse phase space reconstruction study in Shanghai soft X-ray FEL facility
Transverse phase space reconstruction study in Shanghai soft X-ray FEL facility
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DOI：
10.1007/s41365-017-0338-0
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发表时间：
2017
影响因子：
2.8
通讯作者：
Qinglong Yu;D. Gu;Meng Zhang;Minghua Zhao
中科院分区：
文献类型：
--
作者：
Qinglong Yu;D. Gu;Meng Zhang;Minghua Zhao
相空间是描述光束特性的重要参数之一。计算机层析成像技术作为一种相空间重构和束流发射度测量的方法，在过去的几十年里已经被应用于许多加速器中。本文介绍了在上海软X射线自由电子激光装置上进行的横向相空间重构研究。首先，讨论了相空间重构的基本原理以及在归一化相空间中重构光束分布的优点。然后，给出了基于最大熵算法和归一化相空间滤波反投影算法的不同层析成像方法的相空间重建结果。仿真结果表明，通过合理配置相邻屏之间的相位超前，该算法是可行的，具有良好的效率。利用重构的相空间计算了束流发射度和Twiss参数。
Phase space is one of the most important parameters used to describe beam properties. Computer tomography, as a method for reconstructing phase space and measuring beam emittance, has been used in many accelerators over the past few decades. In this paper, we demonstrate a transverse phase space reconstruction study in the Shanghai soft X-ray free electron laser facility. First, we discuss the basic principles of phase space reconstruction and the advantage of reconstructing beam distribution in normalized phase space. Then, the phase space reconstruction results by different computer tomography methods based on the maximum entropy (MENT) algorithm and the filtered back projection algorithm in normalized phase space are presented. The simulation results indicate that, with proper configuration of the phase advance between adjacent screens, the MENT algorithm is feasible and has good efficiency. The beam emittance and Twiss parameters are also calculated using the reconstructed phase space.