CdTe探测器能量刻度与探测效率的模拟计算

摘要

在实现对单能平行光子源的绝对测量之前,需要对CdTe探测器进行刻度.利用已知点源对CdTe探测器进行能量刻度,得到刻度曲线和能量分辨率,利用工业CT对CdTe探测器进行精确扫描,得到CdTe探测器内部结构,并以此为基础,利用MCNP5蒙特卡罗模拟程序建立CdTe探测器物理模型;计算20 ～150 keV能量段,能量间隔为1 keV每个能量点的探测效率,得到CdTe探测器的效率曲线图.发现CdTe探测器在低能段探测效率较高,但Te元素在27 keV和32 keV处产生了逃逸峰,探测效率有所下降,之后探测效率曲线呈现先上升后下降的趋势.%CdTe detector need to be scaled before it detects the single parallel photon source.Based on the energy calibration graph and energy resolution by standard point source,accurate internal structure by CT scanning and the results of physical model calculated by MCNP5 Monte Carlo code can be achived.The detector efficiency graph can be obtained on 1 keV step from 20 keV to 150 keV energy range.The detection efficiency is very well at lower energy range and becomes decline at the energy of 27 keV and 32 keV due to outcome of X-ray escape summits.Then the detector efficiency increases and then decreases with the growth of energy.