北京慢正电子强束流束团化系统设计  

Design of a Pulsing System for Beijing Intense Slow Positron Beam

作　　者：马雁云[1] 裴士伦[2] 曹兴忠[1] 王平[1] 魏存峰[1] 马创新[1] 章志明[1] 王书鸿[2] 王宝义[1] 魏龙[1] 

机构地区：[1]中国科学院高能物理研究所核分析技术重点实验室 [2]中国科学院高能物理研究所加速器中心

出　　处：《高能物理与核物理》2006年第2期166-170,共5页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金(10475096)中国科学院大型仪器专项(U-37)资助~~

摘　　要：慢正电子湮没寿命测量是研究材料表面微观缺陷的重要分析方法．束团化系统是实现慢正电子湮没寿命测量的核心部件,主要由斩波、聚束两部分组成,它可以将随时间连续分布的束流束团化,从而获得正电子湮没寿命测量的时间起点及满足时间分辨率要求的束团．本文以粒子动力学计算为基础,完成了束团化系统的物理设计,其时间分辨率设计值为150ps(FWHM)．The design of a pulsing system for an intense slow positron beam is described in this paper. Slow positron annihilation lifetime measurement is an important method to study the depth-dependent characteristics of the surface and near surface. The start signal for slow positron lifetime measurement can be obtained from the pulsing system, which consists of a reflection type chopper, a prebuncher and a buncher, On the basis of the simulation of dynamics process by Parmela, the frequency of the buncher and the positron energy have been chosen to be 150MHz and,30eV respectively. The designed time resolution of this system is about 150ps （FWHM）.

关 键 词：慢正电子湮没寿命测量束团化 斩波聚束 时间分辨率 能散 

分 类 号：O572.2[理学—粒子物理与原子核物理]