Development and application of the intense slow positron beam at IHEP  

作　　者：王宝义 马雁云 王平 曹兴忠 秦秀波 张哲 于润升 魏龙 

机构地区：[1]Institute of High Energy Physics Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Physics C》2008年第2期156-159,共4页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China (10475096,10575112);Special Fund for Equipment of Chinese Academy of Sciences (U-37)

摘　　要：This paper describes the development and application of an intense slow positron beam at IHEP with regard to its two main components. The Variable-Energy Positron Lifetime Spectroscopy （VEPLS） based on the pulsing system consisting of a chopper, a prebuncher and a buncher has been constructed in order to meet the needs of materials science development. At present, the time resolution of the VEPLS can easily reach about 386 ps with a peak-to-background ratio of about 600：1. A plugged-in ^22Na positron source section for adjusting the newly built experimental station and for increasing the beam operation efficiency has been constructed. A slow positron beam with an intensity of 2.5×10^5 e^＋/s and the beam profile whose diameter is 10 mm has been obtained; the moderation efficiency of the tungsten mesh moderator reaches 5.1×10^-4 as calculated with an original positron source activity of 52 mCi.This paper describes the development and application of an intense slow positron beam at IHEP with regard to its two main components. The Variable-Energy Positron Lifetime Spectroscopy （VEPLS） based on the pulsing system consisting of a chopper, a prebuncher and a buncher has been constructed in order to meet the needs of materials science development. At present, the time resolution of the VEPLS can easily reach about 386 ps with a peak-to-background ratio of about 600：1. A plugged-in ^22Na positron source section for adjusting the newly built experimental station and for increasing the beam operation efficiency has been constructed. A slow positron beam with an intensity of 2.5×10^5 e^＋/s and the beam profile whose diameter is 10 mm has been obtained; the moderation efficiency of the tungsten mesh moderator reaches 5.1×10^-4 as calculated with an original positron source activity of 52 mCi.

关 键 词：plugged-in ^22Na positron source VEPLS time resolution 

分 类 号：O572[理学—粒子物理与原子核物理]