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 ›› 2020, Vol. 31 ›› Issue (3): 31 doi: 10.1007/s41365-020-0732-x


Frequency sensitivity of the passive third harmonic superconducting cavity for SSRF

Xiao-Yun Pu1,2,3 • Hong-Tao Hou4 • Yan Wang4 • Zheng Li1,3 • Jing Shi4 • Yu-Bin Zhao4 • Jian-Fei Liu1,3   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
    3 Shanghai Key Laboratory of Cryogenics & Superconducting RF Technology, Shanghai 201800, China
    4 Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
  • Received:2019-11-21 Revised:2020-01-27 Accepted:2020-02-02
  • Contact: Xiao-Yun Pu
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (No. 11335014).
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Xiao-Yun Pu, Hong-Tao Hou, Yan Wang, Zheng Li, Jing Shi, Yu-Bin Zhao, Jian-Fei Liu. Frequency sensitivity of the passive third harmonic superconducting cavity for SSRF.Nuclear Science and Techniques, 2020, 31(3): 31     doi: 10.1007/s41365-020-0732-x

Abstract: A 1.5 GHz passive third harmonic superconducting cavity was proposed to improve the beam quality and lifetime in the Shanghai Synchrotron Radiation Facility Phase-II beamline project. Lifetime improvement highly depends on the resonant frequency of the passive third harmonic superconducting cavity. It is important that the operating frequency of the cavity is within the design range and the cavity has reasonable mechanical stability. A simulation method for the multiphysics coupled analysis has been developed based on the ANSYS code. Multiphysics coupled simulations have been performed under different conditions, such as etching, evacuation, cooling, and preloading. Analyses of mechanical modes and structural stress have been executed. A possible stiffening ring method for the two-cell superconducting niobium cavity has been investigated. In this paper, we present a multiphysics coupled analysis of the third harmonic cavity using a finite element analysis code. The results of the analysis show that a reliable frequency for the cavity after electron beam welding is 1498.033 MHz, and the corresponding frequency of the pre-tuning goal is 1496.163 MHz. A naked cavity is a reasonable option based on structural stress and mechanical modal analyses. A frequency range of ± 500 kHz and limiting tolerable displacement of ± 0.35 mm are proposed for the design of the frequency tuner.

Key words: Superconducting cavity, Passive harmonic cavity, Frequency detuning, Frequency tuner, Multiphysics analysis