针孔法测量X 光源焦斑尺寸  

X-ray spot size measurement with pinhole

作　　者：李勤[1] 王毅[1] 刘云龙[1] 祁双喜[1] 程晋明[1] 龙全红[1] 李天涛[1] Li Qin;Wang Yi;Liu Yunlong;Qi Shuangxi;Cheng Jinming;Long Quanhong;Li Tiantao(Key Laboratory of Pulsed Power,Institute of Fluid Physics,CAEP,P.O.Box 919-106,Mianyang 621900,China)

机构地区：[1]中国工程物理研究院流体物理研究所,脉冲功率科学与技术重点实验室,四川绵阳621900

出　　处：《强激光与粒子束》2021年第4期95-102,共8页High Power Laser and Particle Beams

基　　金：国防科技专项研究基金项目。

摘　　要：通过针孔成像法得到X光源强度空间分布图像,直接读取图像数据得到X光源的半高宽焦斑(FWHM)尺寸,对图像数据进行傅里叶变换得到调制传递函数,并计算得到X光源的等效焦斑尺寸(50%MTF)。应用针孔成像法测量多脉冲电子直线感应加速器产生的X光源焦斑尺寸,测量结果表明,加速器性能稳定。定义焦斑形状因子参数并用于描述X光源分布,结果表明,该加速器X光源分布在高斯分布和本涅特分布之间变化。The high intense pulse electron beam emitted and accelerated by linear induction accelerator(LIA)is focused to heavy metal target to produce X-ray pulses via bremsstrahlung mechanism.The X-ray is applied to high energy flash radiography.The X-ray spot size is a critical parameter for LIA and the main factor which degrades resolution of the flash radiography.This paper describes a pinhole imaging system measuring the X-ray spot size.The full width at half maximum(FWHM)of the X-ray spot size can be obtained from the pinhole image data.The modulation transfer function(MTF)which is derived from the X-ray spot image by Fourier transform is applied to calculate the 50%MTF spot size.In the continuous experiments of multi-pulse electron linear induction accelerator(MPELIA),the X-ray spot size is measured and the results demonstrate reliable performance of MPELIA.The concept of form factor is introduced,and the measured results show that the MPLIA X-ray spot distribution changes between Gaussian and Bennett distribution.

关 键 词：高能X光焦斑 焦斑尺寸 针孔装置 调制传递函数 形状因子 

分 类 号：TN249[电子电信—物理电子学]