高精度测量射线荧光转换屏YAG晶体的点扩散函数  

High Precision Measurement of Point Spread Function of Fluorescent YAG Scintillator Converter

作　　者：谢红卫[1] 陈进川[1] 李林波[1] XIE Hong-wei;CHEN Jin-chuan;LI Lin-bo(Institute of Nuclear Physics and Chemistry,China Academy of Engineering Physic,Mianyang Sichuan 621900,China)

机构地区：[1]中国工程物理研究院核物理与化学研究所,四川绵阳621900

出　　处：《核电子学与探测技术》2020年第1期156-161,共6页Nuclear Electronics & Detection Technology

基　　金：中国工程物理研究院发展基金(No.2014B0103005,No.2014A0103002);自然科学基金青年基金项日(No.11405156);中国工程物理研究院中子物理学重点实验室基金(No.2015BB01).

摘　　要：从理论和实验两方面研究了伽马射线荧光转换屏YAG晶体的空间分辨的影响因素,建立了高精度直接测量射线荧光转换屏点扩散函数的新方法.理论分析了伽马射线与YAG晶体作用产生次级电子对空间分辨的影响,采用蒙特卡罗程序计算了伽马射线荧光转换屏的空间分辨.使用高灵敏度图像记录系统记录了伽马射线与荧光转换屏YAG晶体作用产生次级电子在出射面上的投影.采用双针孔准直屏蔽体组成的等效超细长厚针孔对钴辐射源进行准直屏蔽,形成了准平行点辐射源射线束,直接获得了射线荧光转换屏的点扩散函数.测得的点扩散函数在半径为12 mm处,相对强度急剧下降为0.1%,并在半径为40 mm位置处逐渐降低为0.08%.The spatial resolution of YAG scintillator as gamma fluorescent converter was theoretically and experimentally studied.A new method of high precision measurement of the point spread function(PSF)of fluorescent converter was proposed.The influence of the secondary electron which was resulted from gamma rays interacting with YAG scintillator on the spatial resolution was theoretically analyzed and the spatial resolution of gamma fluorescent converter was simulated.The projection of the secondary electron was recorded by high sensitive image recording system.A super slim pinhole collimator was constructed with two pinholes to achieve a quasi-parallel point radiation source,and the PSF was directly measured via this point source.The relative intensity of the PSP"sharply decreased to 0.1%at the radius of 12 mm and gradually decreased to 0.08%at the radius of 40 mm.

关 键 词：闪烁体 点扩散函数 荧光弥散 YAG 电子射程 

分 类 号：TN203[电子电信—物理电子学] O411.3[理学—理论物理]