Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2018, Vol. 29 ›› Issue (1): 9 doi: 10.1007/s41365-017-0338-0


Transverse phase space reconstruction study in Shanghai soft X-ray FEL facility

Qing-Lin Yu 1,2 • Duan Gu 1 • Meng Zhang 1 • Ming-Hua Zhao 1   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Contact: Ming-Hua Zhao
Qing-Lin Yu, ·Duan Gu, ·Meng Zhang, ·Ming-Hua Zhao. Transverse phase space reconstruction study in Shanghai soft X-ray FEL facility.Nuclear Science and Techniques, 2018, 29(1): 9     doi: 10.1007/s41365-017-0338-0


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.

Key words: Emittance, Phase space reconstruction, MENT algorithm, SXFEL