偏离中心入射的γ针孔成像系统点扩展函数  

Point Spread Function of Pinhole Imaging System for Deviating from Center of Incidentγ-Ray

作　　者：马庆力[1] 唐世彪[2] 吴彦华[1] 

机构地区：[1]电子工程学院404室,合肥230038 [2]中国科学技术大学近代物理系,合肥230026

出　　处：《光子学报》2015年第3期138-142,共5页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.11375263;11105143)资助

摘　　要：基于蒙特卡罗方法,对γ射线针孔成像系统进行了点扩展函数的模拟研究.采用高斯拟合法比较了入射点中心入射及分别偏离0.5像素、1像素、1.5像素和2像素五种条件下γ射线针孔成像系统的点扩展函数,得出相应系统的调制传递函数,并对空间分辨率进行比较.研究结果表明,当偏离量较小时,利用高斯拟合方法得到的γ针孔成像系统的点扩展函数误差较小,能够满足精度要求;当偏离量较大时拟合误差较大.另外,在针孔与探测器之间加一层理想挡板来减少散射,可以显著地减少拟合误差,提高其空间分辨率.The Point Spread Function（PSF） of a pinhoie imaging system for γ-Ray has been studied through Monte Carlo method. The PSFs under 0,0.5,1,1.5 and 2 pixel bias five different conditions have been obtained and analyzed by fitting the simulating data with Gauss function, the corresponding Modulation Transfer Function（MTF） can be obtained, and the spatial resolutions under these five conditions are compared. As the results show, when the excursion is little, the PSF＇ deviation obtained by Gauss function fitting will be less and can meet the requirement of accuracy, but when the excursion is larger,the fitting deviation will be more. In addition, a ideal baffle between pinhole and detector will reduce the error and improve the spatial resolution remarkably.

关 键 词：针孔成像 点扩展函数 调制传递函数 GEANT4 

分 类 号：TN25[电子电信—物理电子学] TP751[自动化与计算机技术—检测技术与自动化装置]