加速器热中子照相装置CCD芯片屏蔽的模拟计算

Simulation of shielding for a CCD chip of an accelerator-based thermal neutron radiography instrument

建立了研究加速器中子源热中子照相装置CCD芯片屏蔽效果的蒙特卡罗模拟方法,对γ与中子吸收剂量率的模拟计算结果与实验相符。进行了基于9Be(d,n)反应的热中子照相装置屏蔽系统的优化设计,在复杂几何条件下用蒙特卡罗模拟分别计算了CCD芯片在中子、γ混合场中的吸收剂量率和快中子注量率,对CCD相机在辐射场中安全性能进行了评估。

Mont-Carlo simulation was performed for shielding CCD chip of an accelerator-based thermal neutron radiography instrument from the γ-rays and neutrons. The simulation results were comparable with experimental data. The current shielding system was evaluated with this method. The dose rate of γ-rays and neutrons in the CCD chip was calculated and the influence of different shielding materials and geometry on y dose rate and fast neutron flux density in the CCD chip was investigated. The simulation indicates that the current shielding design can satisfy the operation demands of the thermal neutron radiography instrument with thick target ^9Be （d, n） reaction.