宽能域γ射线成像系统研制与初步测试  

Development and Preliminary Test of Wide-Energy-Range Gamma-Ray Imaging System

作　　者：张济鹏 陈晔 张斌 李京伦 ZHANG Jipeng;CHEN Ye;ZHANG Bin;LI Jingun(State Key Laboratory of NBC Protection for Civilian,Beijing 102205,China)

机构地区：[1]国民核生化灾害防护国家重点实验室,北京102205

出　　处：《防化研究》2024年第5期10-18,共9页CBRN DEFENSE

基　　金：国家自然科学基金项目(12205372)。

摘　　要：本文设计了一套测量能量范围为0.3~7 MeV的三层探测器宽能域γ成像系统,每层探测器由硅光电倍增管阵列和像素化掺铈钆铝镓石榴石(Gd_(3)Al_(2)Ga_(3)O_(12):Ce)阵列耦合组成。基于三层探测器记录的两点作用事例,由列表模式极大似然最大期望值法迭代实现了γ射线源的初始能量和空间分布联合重建。经实验测试,成功重建了^(133)Ba、^(137)Cs和^(60)Co点源的图像,并与基于Geant4蒙特卡罗仿真得到的模拟结果进行了比较。测试结果表明,该系统的有效事例率约为2%,对^(133)Ba、^(137)Cs和^(60)Co点源的10次迭代角分辨率分别为8.7°、6.0°和7.3°,且能够同时分辨三个不同方位的^(133)Ba、^(137)Cs和^(60)Co点源;进一步使用14.1MeV中子与水散射产生的3.1MeV、3.7MeV、6.13 MeV和7.12 MeVγ射线数据进行模拟,经初步验证,该系统具有对几兆电子伏特高能γ射线的成像能力。In this paper,a three-layer detector gamma-ray imaging system was designed and implemented,which had a wide energy range of 0.3 to 7 MeV.Each detector consisted of a silicon photomultiplier array coupled with a pixelated gadolinium aluminum gallium garnet(Gd_(3)Al_(2)Ga_(3)O_(12):Ce)array.Based on the two interaction events(2-events)recorded by the threelayer detectors,both the initial energy and spatial distribution of gamma-ray sources were iteratively reconstructed by the list mode maximum likelihood expectation maximization(LMMLEM)algorithm.The images of ^(133)Ba,^(137)Cs and ^(60)Co point sources were successfully reconstructed by experimental tests and compared with the simulation results based on Geant4 Monte Carlo toolkit.The test results showed that the ratio of effective imaging events of the system was about 2%.The angular resolution after 10 iterations for ^(133)Ba,^(137)Cs and ^(60)Co point sources was 8.7°,6.0°and 7.3°,respectively.The three point sources placed in different incident directions could also be distinguished by the imaging system.Furthermore,the 3.1 MeV,3.7 MeV,6.13 MeV and 7.12 MeV gamma-ray data from 14.1 MeV neutron scattering with water target was used for simulation,and the imaging ability of the system for several MeV gamma-rays was preliminarily verified.

关 键 词：康普顿相机 宽能域 γ射线成像系统 闪烁探测器 图像重建 

分 类 号：TL812[核科学技术—核技术及应用]