康普顿成像系统角分辨影响因素的理论及模拟研究

Theoretical and Simulation Study on Factor Affecting Angular Resolution of Compton Imaging System

为了对康普顿成像系统的结构设计提供参考,本文提出了一种理论与模拟计算相结合的对双层位置灵敏CZT晶体组成的康普顿成像系统散射角误差进行估算的方法,并利用该方法对康普顿成像系统散射角误差进行了研究。结果表明,对662 keV、1.33 MeV和2 MeV的入射光子,该成像系统的康普顿散射角误差分别为5.54°、4.82°和4.52°,散射角误差主要来自于探测系统位置分辨本领和能量分辨本领,探测材料多普勒效应引起的角误差相对较小。合理地限制康普顿散射角范围可有效改善成像系统角分辨能力,优化成像效果。

In order to provide the reference for the structural design of Compton imaging system,the method to estimate the scattering angle error of Compton imaging system composed of two-layer position-sensitive CZT crystal by combining theory with simulation calculation was presented,and the scattering angle error of the Compton imaging system was studied by this method.The results show that for incident photons of 662 keV,1.33 MeV and 2 MeV,the Compton scattering angle errors are 5.54°,4.82°and 4.52°,respectively.The scattering angle error mainly comes from the position and energy resolution abilities of the detection system,and the contribution of the angle error caused by the Doppler effect of the detection material is relatively small.Limiting Compton scattering angle range reasonably can improve the angular resolution of imaging system and optimize the imaging effect effectively.