大面积高灵敏度编码相机探测器的设计与性能测试  

Detector design and performance test for coded camera of large area and high sensitivity

作　　者：李岩 王强[1,2] 黄先超[2] 帅磊[2] 曹大泉[2] 张译文[2] 杨曜[2,3] 胡选侯 梁秀佐[2,3] 吴俊 曾国强[1] 章志明 LI Yan;WANG Qiang;HUANG Xianchao;SHUAI Lei;CAO Daquan;ZHANG Yiwen;YANG Yao;HU Xuanhou;LIANG Xiuzuo;WU Jun;ZENG Guoqiang;ZHANG Zhiming(College of Nuclear Technology and Automation Engineering,Chengdu University of Technology,Chengdu 610059,China;Beijing Engineering Research Center of Radiographic Techniques and Equipment,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]成都理工大学核技术与自动化工程学院,成都610059 [2]中国科学院高能物理研究所北京市射线成像技术与装备工程技术研究中心,北京100049 [3]中国科学院大学核科学与技术学院,北京100049

出　　处：《核技术》2020年第5期31-36,共6页Nuclear Techniques

基　　金：核安全监测前沿技术研究及装备研制(No.ZDRW-CN-2018-1)资助。

摘　　要：编码孔径相机是一种定位放射性物质的设备,对丢失放射性物质的寻找以及监测具有重要的意义。为了满足编码孔径相机对核突发事故的污染区进行实时定位,并获得污染面积和污染程度等信息,采用大面积CsI(Tl)晶体阵列与光电倍增管(PhotoMultiplier Tube,PMT)阵列耦合的方式构建高灵敏度编码相机的探测器,以此提高探测效率并减少探测时间。该探测器由121根CsI(Tl)晶体构成11×11的阵列,每根晶体的尺寸为15 mm×15 mm×15 mm,通过光导与3×3的光电倍增管阵列耦合为一个探测器模块;由4个探测器模块组成2×2的阵列作为探头部件,采用自主设计的放大滤波成型以及单端转差分电路实现探测器信号的读出处理。通过测试发现,该探测器模块在662 keV的γ射线激发下,能很好地实现各个晶体条的位置分辨,且其平均能量分辨率为9.4%。测试结果表明:该探测器在位置分辨、能量分辨率、峰位一致性以及探测效率一致性等性能方面均能够满足高灵敏度编码相机成像的设计要求。[Background]The traditional gamma camera cannot locate the contaminated area of nuclear accident,and cannot obtain the information of the contaminated area and degree in real time.[Purpose]This study aims to develop a coded aperture gamma camera detector system with large area and high sensitivity.[Methods]A detector module of large area CsI(Tl)crystal array coupled with photomultiplier tube array was proposed.It consisted of 121 CsI(Tl)crystals at the size of 15 mm×15 mm×15 mm,and 2×2 array composed of 4 detector modules was taken as γ camera detector.Multi-channel readout electronics composed of amplification,filter shaping and single-todifferential conversion circuit was independently designed for readout processing of detector signals.Finally,the performance of this detector system was evaluated by experimental tests.[Results]The results indicate that the detector module can achieve the position resolution,and its average energy resolution is 9.4%under the excitation of 662 keV γ-ray.[Conclusions]The detector system can satisfied the design requirements of coded apertureγcamera of high sensitivity in terms of position resolution,energy resolution,uniformity of peak position and detection efficiency.

关 键 词：位置灵敏探测器 CSI (Tl)晶体阵列 光电倍增管 编码孔径γ 相机 

分 类 号：TL99[核科学技术—核技术及应用]