摘要
n/γ射线双粒子反应深度(Depth of Interaction,DOI)探测器可以实现中子与γ射线甄别并记录粒子在探测器中的反应位置,在对特殊核材料等危险放射性物质的定位成像研究中发挥着重要作用。传统的放射性定位成像装置都依赖具有n/γ射线甄别能力的探测器阵列,从而导致成像测量装置结构复杂、成本高。针对此问题,设计了一种基于EJ276塑料闪烁体(Φ3 cm×15 cm)的双粒子反应深度探测器,采用硅光电倍增管在闪烁体两端进行信号读出,并综合利用两端信号幅度与飞行时间对比进行粒子反应位置确定。利用Am-Be中子源和137Cs γ源对探测器进行参数优化和分辨率刻度,结果显示:该探测器在灵敏区内探测效率均匀性较好,反应位置分辨率约4.4 cm。
[Background]Recently,global concerns regarding the illicit transportation and trafficking of nuclear materials and other radioactive sources have increased,leading to increased demands for efficient and rapid security and non-proliferation technologies.The International Atomic Energy Agency's Incident and Trafficking Database has reported 3235 confirmed incidents involving nuclear and other radioactive materials out of regulatory control from 1993 to 2017.Of these incidents,278 are associated with trafficking or malicious use of materials such as highly enriched uranium,plutonium,and plutonium-beryllium neutron sources.Therefore,developing depth-of-interaction detector for neutrons and gamma rays is important for effective control of nuclear and radiation materials at national and international cross points such as borders,ports,and airports.[Purpose]This study aims to design a depth-of-interaction detector for neutrons and gamma rays and characterize its performance.[Methods]Hereby,an EJ276 plastic scintillator(Φ3 cm×15 cm)coupled with two silicon photomultipliers(SiPMs)in both sides was designed as a depth-of-interaction detector for neutrons and gamma rays.The short gate time was optimized to achieve better neutron/gamma-ray discrimination,and the reaction position was determined based on the amplitude ratio and time of flight(TOF)difference between signals from two sides.Finally,Am-Be neutron source and 137Csγsource were applied to detector parameter optimization and resolution calibration for performance characterization.[Results]Experimental results demonstrate that good consistency in the detection efficiency of the detector at different incident positions,where the resolution of the one-dimensional reaction position is approximately 4.4 cm.[Conclusions]The designed depth-of-interaction detector can be used toreplace detector arrays in neutron scatter cameras and coded-aperture imagers to reduce costs and system complexity.
作者
赵冬
梁旭文
张荣华
黑大千
贾文宝
单卿
凌永生
ZHAO Dong;LIANG Xuwen;ZHANG Ronghua;HEI Daqian;JIA Wenbao;SHAN Qing;LING Yongsheng(College of Material Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210000,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China)
出处
《核技术》
CAS
CSCD
北大核心
2023年第7期53-60,共8页
Nuclear Techniques
基金
国家自然科学基金(No.11975121)
江苏省研究生科研与实践创新计划项目(No.KYCX22_0354)资助。
关键词
反应深度探测器
塑料闪烁体
n/γ甄别
位置分辨率
Depth-of-interaction detector
Plastic scintillator
Neutron/gamma-ray discrimination
Position resolution
