Nuclear Techniques ›› 2019, Vol. 42 ›› Issue (8): 80201-080201.doi: 10.11889/j.0253-3219.2019.hjs.42.080201


Radio frequency design and multipacting study of superconducting elliptical cavity for CSNS-II linac

Bo LI1,2,Huachang LIU1,2,Yun WANG1,2,Xiaolei WU1,2,Peihua QU1,2,Ahong LI1,2,Mengxu FAN1,2,Qiang CHEN1,2   

  1. 1. Dongguan Institute of Neutron Science, Dongguan 523803, China
    2. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • Received:2019-05-05 Revised:2019-06-19 Online:2019-08-10 Published:2019-08-26
  • About author:LI Bo, male, born in 1986, graduated from University of Science and Technology of China in 2012, master student, focusing on new structure for proton linac
  • Supported by:
    National Natural Science Foundation of China(11105166)

Abstract: Background

Upgrade of China spallation neutron source (CSNS-II) from 100 kW to 500 kW is being developed. Superconducting spoke cavity and elliptical cavity are used to upgrade the linac from 80 MeV to 300 MeV, hence the 648 MHz β=0.6 elliptical cavity needs to be studied.


The study aims to develop this β=0.6 elliptical cavity for CSNS-II linac upgrade, which provides energy gain from 150 MeV to 300 MeV.


With software computer simulation technology (CST), the cavity geometry and high frequency parameters of ellipsoidal cavity were optimized. Multipacting and Lorentz force were analyzed with these optimized data.


The field flat of this elliptical cavity was optimized to 98.2% while the E pk/E acc and B pk/E acc reached 2.70 and 4.89, respectively. With modified the shape of the equator the growth rate of multipacting decresed under the same radio frequency (RF) parameters, and multipacting was suppressed totally when the accelerated gradient was over 8 MV?m-1.


The RF parameters of this 648 MHz β=0.6 elliptical cavity after optimization design could meet the requirements of CSNS-II linac upgrade very well.

Key words: Superconducting, Elliptical cavity, Multipacting, Lorentz force

CLC Number: 

  • TL503.1