便携式γ射线照射装置散射辐射特性研究

便携式γ射线照射装置对于提高固定式X、γ辐射剂量仪检定率、解决现场校准难题具有重要意义，利用蒙特卡罗模拟与实验测量协同开展便携式γ射线照射装置散射辐射特性研究。结果表明：蒙特卡罗方法可以模拟得到装置自身的散射辐射，实验测量只能获得照射装置以外辐射场中的散射辐射。利用MCNP程序F4卡和CF卡得到距放射源1 m处照射装置自身的散射贡献分别为13.07 %和4.55 %；反平方律实验和移出实验得到辐射场散射辐射贡献分别为0.2 %和3.94 %，满足ISO 4037-1:2019和GB/T 12162.1-2000的要求。该装置可用于固定式X、γ辐射剂量仪的现场校准。

Research on Scattered Radiation for Portable Gamma Ray Irradiating Facility

The portable gamma ray irradiating facility is of great significance for improving the examined rate of fixed X and gamma ray dosimeters and solving the problem of on-site calibration.To study the scattered radiation of portable irradiating facilities,the Monte Carlo and PTW ionization chambers were used for simulation and experimental measurement.The results demonstrate that the scattered radiation caused by the facility itself can be simulated by the Monte Carlo method,while only the scattered radiation caused by the reference radiation field can be measured in the experiment.The scattered radiation caused by the portable irradiating facility at a distance of 1 m is 13.07 % and 4.55 % respectively when the MCNP program F4 card and cell flag are used.The scattered radiation caused by the reference radiation field are 0.2 % and 3.94 % calculated by the inverse square of the focus to detector distance experiment and removal experiment,which satisfied the requirements of ISO 4037-1:2019 and GB/T 12162.1-2000.The facility can be used to calibrate the fixed environmental X and gamma radiation dose rate monitoring instrument on site.