Effect of the transverse parasitic mode on beam performance for the ADS driver linac in China

• Published in: Chinese physics C Vol. 39; no. 5; pp. 92 - 97
• Main Author: 程鹏 裴士伦 王九庆 李智慧
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing 01.05.2015
• Subjects: ADS; beam dynamics; beam instability; Beams (radiation); China; Deterioration; dipole mode; Dipoles; Dynamic tests; Dynamical systems; HOM; Injectors; Linear accelerators; parasitic mode; 中国; 光束; 加速器驱动次临界系统; 寄生; 性能; 直线加速器; 驱动程序
• ISSN: 1674-1137; 0254-3052
• DOI: 10.1088/1674-1137/39/5/057002

The ADS （Accelerator Driven subcritical System） driver linac in China is designed to run in CW （Continuous Wave） mode with 10 mA designed beam current. In this scenario, the beam-induced parasitic modes in the ADS driver linac may make the beam unstable or deteriorate the beam performance. To evaluate the parasitic mode effect on the beam dynamics systematically, simulation studies using the ROOT-based numerical code SMD have been conducted. The longitudinal beam instability induced by the HOMs （High Order Modes） and SOMs （Same Order Modes） has little effect on the longitudinal beam performance for the current ADS driver linac design based on the 10 MeV/325 MHz injector I from previous studies. Here the transverse parasitic mode （i.e., dipole HOM） effect on the transverse beam performance at the ADS driver linac exit is investigated. To more reasonably quantify the dipole mode effect, the multi-bunch effective emittance is introduced in this paper.