CSNSⅡ离子源及LEBT真空系统  

Vacuum System for CSNSⅡIon Source and LEBT

作　　者：刘顺明 宋洪 王鹏程[1,2] 刘佳明 关玉慧[1,2] 谭彪 孙晓阳[1,2] 陈卫东 刘盛进[1,2] 欧阳华甫 LIU Shun-ming;SONG Hong;WANG Peng-cheng;LIU Jia-ming;GUAN Yu-hui;TAN Biao;SUN Xiao-yang;CHEN Wei-dong;LIU Sheng-jin;OUYANG Hua-fu(Spallation Neutron Source Science Center,Dongguan 523808,China;Institute of High Energy Physics,Chinese Academy of Sciences(CAS),Beijing 100049,China)

机构地区：[1]散裂中子源科学中心,广东东莞523808 [2]中国科学院高能物理研究所,北京100049

出　　处：《真空》2022年第4期22-27,共6页Vacuum

基　　金：国家自然科学基金面上项目(NO.11875271)。

摘　　要：CSNSⅡ加速器的束流打靶功率从100kW升级至500kW,要求直线加速器平均束流功率从目前的5kW提高到25kW,脉冲束流强度从目前的12.5mA提高到大于40mA。为此,需将当前使用的潘宁(Penning)型表面负氢离子源更改为射频(RF)负氢离子源。考虑到切束器的切束比范围在35%~50%,LEBT通过率可达到75%~95%,故RF负氢离子源需要产生至少50mA的负氢离子束。负氢离子源氢气用量也需要由目前的10sccm提高至不低于20sccm,同时要求LEBT第二腔真空度≤5.0×10^(-3)Pa。基于此,本文对离子源及LEBT真空系统进行了改造,提高了LEBT的束流通过率。并且对比了国内外两款磁悬浮分子泵对氢气的抽速,为后期分子泵的选型以及国产化替代提供一定的参考。The beam power of the CSNSⅡaccelerator will be upgraded from 100kW to 500kW,which requires the average beam power of the linear accelerator to be increased from the current 5kW to 25kW,and the pulse beam intensity to be increased from 12.5mA to more than 40mA.For this reason,the Penning type surface negative hydrogen ion source currently in use will be replaced by a radio frequency(RF)negative hydrogen ion source.Considering that the beam cutting ratio of the beam chopper ranges from 35%to 50%,and the LEBT transmission rate can reach 75%to 95%,the RF negative hydrogen ion source needs to produce a negative hydrogen ion beam of at least 50mA.Therefore,the hydrogen gas consumption of the ion source needs to be increased from the current 10sccm to more than 20sccm,and the pressure of LEBT second chamber is required to be≤5.0×10^(-3)Pa.Based on this,the ion source and the LEBT vacuum system are modified in this paper,and the beam transmission rate of LEBT is improved.In addition,the pumping speed of hydrogen with two domestic and imported magnetic levitation molecular pumps is compared,which provides a certain reference for the selection of molecular pumps and localized substitution.

关 键 词：RF负氢离子源 LEBT真空系统 分子泵系统改造 氢气抽速 

分 类 号：TB75[一般工业技术—真空技术]