摘要
高能电子照相是一种新兴的无损探测技术,可以在不拆解客体的情况下对客体材料及其内部结构进行定量测量。与高能质子照相相比,其分辨能力更高,可达到亚μm量级,有望成为介观现象诊断的有力工具。为研究相互作用和成像束线对成像模糊度的影响,采用Geant4模拟软件,建立12GeV电子束从客体到像平面全过程照相模型,主要分析了成像束线引起的色差模糊、客体纵向长度引起的模糊以及次级粒子造成的模糊。研究结果表明,高能电子照相成像模糊为亚μm量级,其中成像束线引起的色差模糊为主要贡献项,次级粒子和客体纵向长度引起的模糊可以忽略。
High energy electron radiography(eRad)can quantitatively measure target material and its internal structure without taking target apart,it is a new NDT(nondestructive testing)technique.Compared with high energy proton radiography,eRad has submicron resolution and promises to be a powerful tool for mesoscale diagnosis.Its image blur is a crucial point that needs to be deeply studied.To study the influence of interaction and imaging beamline on image blur,numerical simulation using the Monte Carlo code Geant4 has been implemented,including the entire physics process of 12 GeV electron beam travelling through the object and beamline and arriving at the image plane.This article mainly analyzes the chromatic aberration of the imaging beamline,the blur of the longitudinal length of target and the influence of secondary particles using this model.The result shows that the scale of image blur in eRad is just submicron and most blur is caused by imaging beamline,the influence of longitudinal length of target and secondly particle can be neglected.
引文
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