高能X射线能谱测量中衰减材料特性影响

王毅; 叶毅; 李勤; 杨治勇; 荆晓兵; 代志勇

doi:doi:10.11884/hplpb201628.014004

强激光与粒子束, 2016, 28 (1): 014004, 网络出版: 2016-03-22

高能X射线能谱测量中衰减材料特性影响

Impact of filter material properties in high-energy X-ray spectrum estimation

论文大纲

王毅 ^*叶毅李勤杨治勇荆晓兵代志勇

作者单位

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

X射线能谱衰减材料质量衰减系数蒙特卡罗方法 X-ray spectrum filter material mass attenuation coefficient Monte Carlo method

摘要

基于衰减透射原理的高能X射线能谱测量,采用蒙特卡罗成像模拟的方法研究衰减材料选择对能谱准确稳定重建的影响。设计多孔准直模型模拟X射线穿过不同衰减材料的透射过程,并在单次成像中获得完整的衰减透射率曲线。由衰减透射率求解能谱是一种病态条件问题,采用改进的迭代扰动法进行解谱,计算时考虑透射率计算值与真实值的差异最小化要求以及高能能谱分布曲线的平滑性特点。通过计算分析了材料在能谱范围内的衰减特性变化趋势与能谱准确稳定重建的内在联系。结果表明,选用材料的质量衰减系数需满足在整个能谱分布范围内单调递减的要求。

Abstract

Monte Carlo imaging simulation is applied to investigate the impact of filter material properties on accurate and robust reconstruction of the high-energy X-ray spectrum based on the attenuated transmission principle. A model of multi-collimating apertures is designed to simulate the process of X-ray passing through filter materials, and an entire attenuation transmission curve is obtained in a single imaging simulation. It is an ill-conditioned problem to obtain the X-ray spectrum from the transmission data. An improved iterative perturbation method is used to reconstruct the spectrum, which considers minimization of the difference between the calculated and the true transmission curves and smoothness of the high-energy spectrum function. The inherent relation between the attenuation characteristic of the filter material and the accurate-and-robust reconstruction of the spectrum is also verified. The results show that the mass attenuation coefficient of the filter material should be monotonically decreasing over the spectrum.

参考文献

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王毅, 叶毅, 李勤, 杨治勇, 荆晓兵, 代志勇. 高能X射线能谱测量中衰减材料特性影响[J]. 强激光与粒子束, 2016, 28(1): 014004. Wang Yi, Ye Yi, Li Qin, Yang Zhiyong, Jing Xiaobing, Dai Zhiyong. Impact of filter material properties in high-energy X-ray spectrum estimation[J]. High Power Laser and Particle Beams, 2016, 28(1): 014004.

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