蒙特卡罗方法在γ剂量率灵敏度标定中的应用

THE APPLICATION OF MONTE CARLO METHOD IN SENSITIVITY CALIBRATION OF GAMMA RAY DOSE RATE

在γ剂量率测量标定中，使用ＧＤ－４０管作为γ探头来测量γ剂量率。实验室标定γ探头灵敏度在钴源上进行，６０Ｇｏ源平均能量为１．２５ＭｅＶ，而在实际测量中，辐射场的γ射线包含了各种能量成份，因此对实验室标定的灵敏度在实际应用中就需要进行修正。本工作通过蒙特卡罗粒子输运模拟方法，计算了单能与辐射场能谱的剂量比值，给出了修正因子，从而使γ剂量率灵敏度标定更加准确。

In the process of measurement and calibration of gamma ray dose rate,GD 40 is used as gamma ray detector to measure gamma ray dose rate. The laboratory calibration of detector sensitivity is done in 60 Co gamma ray source. 60 Co gamma ray average energy is 1.25 MeV. When the detector is used for practice radiation field, its energy spectrum is significantly different, so the sensitivity of laboratory calibration must be corrected. Using the method of Monte Carlo particle transportation simulation, the ratio of doses of the radiation with a given energy spectrum that of a mono energy(1.25 MeV) radiation is calculated as the correction coefficient. The method is described and the results are given for a GD 40 detector.