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 (5): 74 doi: 10.1007/s41365-018-0399-8


Sub-picosecond electron bunch length measurement using coherent transition radiation at SXFEL

Yu Bian 1,2 • Wen-Yan Zhang 1 • Bo Liu 1 • Dong Wang 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 123
  • Contact: Dong Wang
  • Supported by:

    This work was supported by the National Program on Key Basic Research Project (No. 2016YFA0401900) and the Ministry of Science and Technology of China.

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Yu Bian, Wen-Yan Zhang, Bo Liu, Dong Wang. Sub-picosecond electron bunch length measurement using coherent transition radiation at SXFEL.Nuclear Science and Techniques, 2018, 29(5): 74     doi: 10.1007/s41365-018-0399-8


Longitudinal electron bunch length plays a significant role in single-pass free-electron lasers (FEL), as the high-gain FEL process depends strongly on the high peak current of electron bunches. Longitudinal electron bunch length was measured by detecting the interferogram of coherent transition radiation generated by electron bunches using a THz interferometer and a Golay cell (spectral range 0.02–20 THz) at Shanghai X-ray free-electron laser. The detailed process of measurement and data analysis are discussed herein. Furthermore, the electron bunch length was estimated based on the dispersive strength R56 of the bunch compressor and the energy spread δ of electron bunches, which were obtained via experiments. The comparison showed that the measured bunch length was consistent with the estimated bunch length.

Key words: Electron bunch length, THz interferometer, Coherent transition radiation, Beam diagnostics