权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Measurement of annihilation cross sections for positrons with inner-shell electrons

具有内壳层电子的正电子湮灭截面的测量

基本信息

批准号：
14540371
负责人：
NAGASHIMA Yasuyuki
金额：
$ 2.37万
依托单位：
Tokyo University of Science (2003)The University of Tokyo (2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540371/
关键词：
positrons inner-shell electrons annihilation cross sections characteristic X-rays ionization イオン化断面積

项目摘要

The purpose of this project is to measure the cross sections for positron annihilation with inner-shell electrons by detecting the positron annihilation induced characteristic X-rays.There are two kinds of difficulties :(i)The positron annihilation rates with inner-shell electrons are extremely low.(ii)The γ-rays emitted from positron annihilation in the taregets deposit part of their energy in the X-ray detector crystal and produce a background in the X-ray spectra.In order to succeed in measuring the cross sections, the background must be suppressed and the positron annihilation induced characteristic X-rays must be detected.The background can be suppressed if an X-ray detector with a thin Si(Li) crystal is used. In this project, this kind of detector has been developed and employed to measure the cross sections. However, the cross sectiohs have not yet been measured in the term of this project.This project will be continued.In the project, the characteristic X-rays by positron impact have been successfully detected using the new detector.The inner-shell ionization cross sections by positron impact have also been measured successfully using this detector.The results have been submitted to ajoumal and accepted.

本项目的目的是通过探测正电子湮没产生的特征X射线来测量正电子与内壳层电子的湮没截面，其困难有两点：（1）正电子与内壳层电子的湮没率很低;（ii）靶区正电子湮没产生的γ射线，其能量的一部分存款在X射线探测器晶体中，并在X射线谱中产生背景，为了成功地测量截面，必须抑制背景，并探测正电子湮没产生的特征X射线，如果使用薄Si（Li）晶体的X射线探测器，背景可以被抑制。在本项目中，开发了这种探测器并用于测量横截面。在本项目中，利用新的探测器成功地探测到了正电子碰撞的特征X射线，并测量了正电子碰撞的内壳层电离截面，其结果已提交给原子科学院，并被认可。