CSNS RCS注入横向相空间涂抹的研究(英文)

Studies of Transverse Phase Space Painting for the CSNS RCS Injection

中国散裂中子源(CSNS)加速器系统由80MeV的直线加速器和1.6GeV的快循环同步加速器(RCS)构成.CSNS第一阶段采用H^-剥离注入方法,将粒子数累积至1.88×10^(13).注入束流被涂抹在较大的横向相空间内,以减小空间电荷效应.粒子注入后,为了降低由空间电荷效果引起的工作点漂移和工作点弥散,束流分布的均匀性很重要.引入了评估束流分布均匀性的三个参数.为了抑制注入过程中束流发射度和束晕的增长,通过采用三维的模拟程序ORBIT,对不同的横向相空间涂抹方案进行了比较.同时还介绍了工作点、注入峰值流强和斩波调制比等因素对注入过程的影响.

The China Spallation Neutron Source （CSNS） accelerators consist of an 80MeV proton linac, and a 1.6GeV rapid cycling synchrotron. The ring accumulates 1.88×10^13 protons via H^-stripping injection in the phase CSNS-Ⅰ. The injected beam is painted into a large transverse phase space to alleviate spacecharge effects. The uniformity of the beam emittance after the injection is important in reducing the tune shift/spread due to the space-charge effects. The paper introduces three parameters to evaluate the uniformity of a beam distribution. To control emittance growth and reduce halo generation, different painting schemes have been compared by using the 3D simulation code ORBIT. The detailed studies on painting schemes and the dependence on the lattice tune, the injection peak current, and chopping rate are also presented.