HPGe探测效率和符合相加修正系数的蒙特卡罗计算

目的 介绍用蒙特卡罗(MC)方法编写的计算HPGe探测器探测效率和符合相加修正系数的程序(Cool 2000-HpGe),及实验值与计算值的比较研究。方法 用MC计算得到的探测效率和符合相加修正系数与实验得到的值进行比较。结果 对空气、水和土壤三种模拟基质体标准源由实验(ORTEC ADCOM100+GEM50195 HPGe γ谱仪系统)得到的符合相加修正系数值与模拟计算值之间的相对偏差绝对值分别为5.14%、12.1%和10.4%,在点源距探测器端窗5、10和25 cm处的由实验得到的探测效率值与模拟计算值之间的相对偏差绝对值分别为10.6%、5.6%和3.0%。结论 笔者报道的MC计算软件Cool 2000可以在环境放射性监测中用于计算HPGe探测器探测效率和符合相加修正系数。

Monte-Carlo Calculations of HPGe Detection Efficiency and Coincidence-summing Correction

Objective This paper introduces a Monte-Carlo program Cool 2000 for calculating HPGe detection efficiency and coincidence-summing correction.It employs Monte Carlo emulation (MC) technique for calculating detection efficiency and coincidence-summing correction of HPGe gamma spectrometry system.Methods The program is written in Fortran and tested with 3 types of volume calibration sources simulating air, water and soil samples, respectively, and each source contained 8 radionuclides.Results The results proved that the relative differences of calculated and actually measured coincidence-summing corrections were within ±5.14%, ±12.1% and ±10.4%, respectively.Tests also made for point source at distances to detector of 5cm, 10cm and 25cm, respectively.It indicated that the relative differences of measured and calculated efficiencies were within ±10.6%, ±5.6% and ±3.04%, respectively.Conclusion The reported MC program Cool 2000 is applicable to environmental radiation monitoring for calculating HPGe detection efficiency and coincidence-summing correction.