Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (6): 60103-060103.doi: 10.11889/j.0253-3219.2016.hjs.39.060103


Study on twin input coupler for a 1.5-GHz superconducting cavity

XIE Xinhua1,2,3, WANG Yan1,2, MA Zhenyu1,2, SHI Jing1,2, LUO Chen1,2, LI Zheng1,2, MAO Dongqing1,2, FENG Ziqiang1,2, HOU Hongtao1,2, LIU Jianfei1,2   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China;
    2 Shanghai Key Laboratory of Cryogenics & Superconducting Radio Frequency Technology, Shanghai 201800, China;
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-03-10 Revised:2016-04-06 Online:2016-06-10 Published:2016-06-12
  • Supported by:

    Supported by National Natural Science Foundation of China (No.11335014)


Background: The 1.5-GHz 5-cell superconducting cavity designed by the Shanghai Key Laboratory of Cryogenics & Superconducting Radio Frequency Technology was optimized to accelerate a high current electron beam under continuous wave (CW) operation mode. Purpose: Considering the accelerating gradient 15-20 MV?m-1, it is necessary to use twin input coupler. Methods: Electromagnetic simulations of the input coupler were implemented using CST (Computer Simulation Technology), and the results showed a 18-MHz bandwidth where standing-wave ratio was better than 1.05. Power feeding by two couplers was calculated theoretically and testified on a set-up. Results: Theoretical derivation and experimental results showed an enhancing when both couplers were under coupled but a reduction to the weaker coupled one when both couplers were over coupled. Results from simulations showed that transverse kick to beam can be diluted drastically even when difference of insert depths is 1mm. Conclusion: Adopting twin input coupler is the only option for high average beam current CW accelerator.

Key words: Twin input coupler, Coupling parameter, Coupler kick

CLC Number: 

  • TL503.2