Conception design of helium ion FFAG accelerator with induction accelerating cavity  

作　　者：罗焕丽 徐玉存 王相綦 徐宏亮 

机构地区：[1]National Synchrotron Radiation Laboratory, University of Science and Technology of China [2]China Electronics Technology Group Corporation No.38 Research Institute

出　　处：《Chinese Physics C》2013年第9期48-54,共7页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(11045003)

摘　　要：In the recent decades of particle accelerator R＆D area, the fixed field alternating gradient （FFAG） accelerator has become a highlight for some advantages of its higher beam intensity and lower cost, although there are still some technical challenges. In this paper, the FFAG accelerator is adopted to accelerate a helium ion beam on the one hand for the study of helium embrittlement on fusion reactor envelope material and on the other hand for promoting the conception research and design of the FFAG accelerator and exploring the possibility of developing high power FFAG accelerators. The conventional period focusing unit of the helium ion FFAG accelerator and three- dimensional model of the large aperture combinatorial magnet by OPERA-TOSCA are given. For low energy and low revolution frequency, induction acceleration is proposed to replace conventional radio frequency （RF） acceleration for the helium ion FFAG accelerator, which avoids the potential breakdown of the acceleration field caused by the wake field and improves the acceleration repetition frequency to gain higher beam intensity. The main parameters and three-dimensional model of induction cavity are given. Two special constraint waveforms are proposed to refrain from particle accelerating time slip （AT） caused by accelerating voltage drop of flat top and energy deviation. The particle longitudinal motion in two waveforms is simulated.In the recent decades of particle accelerator R＆D area, the fixed field alternating gradient （FFAG） accelerator has become a highlight for some advantages of its higher beam intensity and lower cost, although there are still some technical challenges. In this paper, the FFAG accelerator is adopted to accelerate a helium ion beam on the one hand for the study of helium embrittlement on fusion reactor envelope material and on the other hand for promoting the conception research and design of the FFAG accelerator and exploring the possibility of developing high power FFAG accelerators. The conventional period focusing unit of the helium ion FFAG accelerator and three- dimensional model of the large aperture combinatorial magnet by OPERA-TOSCA are given. For low energy and low revolution frequency, induction acceleration is proposed to replace conventional radio frequency （RF） acceleration for the helium ion FFAG accelerator, which avoids the potential breakdown of the acceleration field caused by the wake field and improves the acceleration repetition frequency to gain higher beam intensity. The main parameters and three-dimensional model of induction cavity are given. Two special constraint waveforms are proposed to refrain from particle accelerating time slip （AT） caused by accelerating voltage drop of flat top and energy deviation. The particle longitudinal motion in two waveforms is simulated.

关 键 词：FFAG helium embrittlement induction acceleration constraint waveform 

分 类 号：O572.211[理学—粒子物理与原子核物理]