Dual-cavity beam arrival time monitor design for the Shanghai soft X-ray FEL facility

  • Shan-Shan Cao
  • Ren-Xian Yuan
  • Jian Chen
  • Yong-Bin LengEmail author


Free electron lasers provide high-power and ultrashort pulses with extreme brightness. In order to improve a facility’s capabilities and explore the possibility of performing high-resolution time-resolved experiments, a beam arrival time resolution under 100 fs is required. In this article, a novel beam arrival time monitor (BAM) equipped with two cavities has been designed and a beam flight time measurement scheme based on the BAM prototype has been proposed to estimate phase jitter in the signal measurement system. The two BAM cavities work at different frequencies and the frequency difference is designed to be 35 MHz. Therefore, a self-mixing intermediate frequency signal can be generated using the two cavities. The measured beam flight time shows a temporal deviation of 37 fs (rms).


Beam arrival time monitor Dual-cavities Beam flight time Self-mixing 



The authors thank the operation team of SXFEL for its assistance in conducting the beam experiment.


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Copyright information

© China Science Publishing & Media Ltd. (Science Press), Shanghai Institute of Applied Physics, the Chinese Academy of Sciences, Chinese Nuclear Society and Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Shan-Shan Cao
    • 1
    • 2
  • Ren-Xian Yuan
    • 1
  • Jian Chen
    • 1
    • 2
  • Yong-Bin Leng
    • 1
    Email author
  1. 1.Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghaiChina
  2. 2.University of Chinese Academy of SciencesBeijingChina

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