NaI(Tl)探测器测量空气吸收剂量率方法研究

Study on the method of air absorbed dose rate measurement by NaI(Tl)detector

本文基于Φ7.5 cm×7.5 cm NaI(Tl)探测器,开展测量γ射线空气吸收剂量率方法的研究。使用蒙特卡罗方法对NaI(Tl)探测器进行仿真模拟,获取探测器50 keV~2.5 MeV能量范围的γ射线能谱图。利用G(E)函数对放射源空气吸收剂量率进行计算,求解G(E)函数时考虑Kmax与优化因子M对其计算空气吸收剂量率产生的影响,对G(E)函数的求解进行优化以提高计算精度。经过优化的G(E)函数计算的空气吸收剂量率与理论标准值相对偏差S低于±1%。最后经过实验测量对比发现,G(E)函数空气吸收剂量率计算结果与剂量率仪测量结果相对偏差小于±10%,说明经过优化得到的NaI(Tl)探测器G(E)函数值可以用于空气吸收剂量率的测量应用。

This study investigated a method of measuring the absorbed dose rate ofγ-ray in air using aΦ7.5 cm×7.5 cm NaI(Tl)detector.Simulation of the NaI(Tl)detector using the Monte Carlo method was performed to obtain theγ-ray energy spectrum of the detector in the energy range of 50 keV~2.5 MeV.The G(E)function was used to calculate the air-absorbed dose rate of radioactive sources.When solving the G(E)function,the influence of the K max and the optimization factor M on its calculation of the air-absorbed dose rate was considered,and the solution of the G(E)function was optimized to improve the calculation accuracy.The relative deviation S of the air absorbed dose rate calculated by the optimized G(E)function from the theoretical standard value was less than±1%.Finally,after the comparison of experimental measurements,it was found that the relative deviation between the calculated air absorbed dose rate of the G(E)function and the measured results of the dose rate meter was less than±10%,indicating that the optimized G(E)function value of the NaI(Tl)detector can be used for the application of air absorbed dose rate measurement.