Frequency sensitivity of the passive third harmonic superconducting cavity for SSRF  

作　　者：Xiao-Yun Pu Hong-Tao Hou Yan Wang Zheng Li Jing Shi Yu-Bin Zhao Jian-Fei Liu 

机构地区：[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

出　　处：《Nuclear Science and Techniques》2020年第3期85-93,共9页核技术（英文）

基　　金：supported by the National Natural Science Foundation of China(No.11335014)

摘　　要：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.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.

关 键 词：Superconducting cavity Passive harmonic cavity Frequency detuning Frequency tuner Multiphysics analysis 

分 类 号：TL594[核科学技术—核技术及应用]