采用硅光电倍增管和塑闪阵列的便携式快中子成像系统的可行性研究  

Feasibility study of portable fast neutron imaging system using silicon photomultiplier and plastic scintillator array

作　　者：张雨 张健 张国光[1] ZHANG Yu;ZHANG Jian;ZHANG Guoguang(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《核技术》2021年第3期46-53,共8页Nuclear Techniques

摘　　要：介绍了一种基于硅光电倍增管和塑料闪烁体阵列的小型快中子成像系统。对比X射线成像,快中子成像对低原子序数构成的物质更加灵敏,在工业领域有重要应用。从模拟和实验两方面探讨方案的可行性。利用GEANT4和Python搭建了一套模拟平台,实现从中子到电信号的全物理过程模拟,根据结果进行了图像重建。通过模拟,讨论了能量阈值、闪烁体尺寸对系统探测效率的影响;论述了影响系统成像效果的几个关键因素(中子源焦点大小、源与样品间距、样品的材质和厚度等)。试制了一个小尺寸的成像探测器,并配合氘-氘中子管,对聚乙烯材质的样品进行了成像实验。结果显示:此单元成像效果基本与模拟效果一致,成像图的实际像素尺寸可以达到3 mm×3 mm。以上模拟和实验结果显示基于硅光电倍增管快中子成像系统的可行,为进一步的研究提供了依据。[Background]The fast neutron imaging is an important non-destructive screening method which is sensitive to the objects consisting of the low atomic number elements such as hydrogen and carbon.A small,portable fast neutron imaging system could have a number of applications such as domestic security and industrial testing.[Purpose]This study aims to investigate the feasibility of a portable fast neutron imaging system based on the plastic scintillator array and silicon photomultiplier(SiPM).[Methods]First of all,a simulation toolkit was developed by using GEANT4 and Python programming language to obtain the position and the deposited energy of a neutron interacting with the plastic scintillator.Then,several samples of different materials and shapes were simulated with this toolkit,and the reconstructed images of these samples were established.Based on the simulation results,factors affecting detection efficiency of detector,such as energy threshold and the size of the scintillator,were analyzed.Some factors related with the image quality,like the size of the neutron source,the distance between the source and the sample,etc.,were studied by the simulation.Finally,a prototype detector for neutron imaging system in the size of 5.5 cm×5.5 cm×2.5 cm was developed and experimental test of several samples in simulation were performed using a D-D neutron tubes.[Results]Experimental data obtained by the prototype neutron imaging system using silicon photomultiplier and plastic scintillator array show that different materials and shapes of samples can be preliminarily distinguished from the reconstructed images with spatial resolution of 3 mm.[Conclusions]The feasibility of the imaging system based on SiPM and the plastic scintillator array is demonstrated from two aspects of simulation and experiment in this study.

关 键 词：快中子成像 蒙特卡罗模拟 硅光电倍增管 位置灵敏探测阵列 

分 类 号：TL99[核科学技术—核技术及应用]