碘化钠探测器对不同能量的γ射线存在不同的能量响应，为了使其测量γ辐射剂量的准确度达到要求，需要对碘化钠探测器进行能响补偿。本项目利用MCNP软件，模拟尺寸为Φ30 mm ×20 mm的碘化钠晶体在不同铅屏蔽体模型下的能量响应；通过比较不同模型下能量响应的标准偏差，选出最佳铅屏蔽体的形状和尺寸。模拟得出铅屏蔽体的尺寸在4 mm厚度，小孔半径r为6．7 mm（暴露面积20％）时，碘化钠晶体的能量响应最好。通过实验验证，理论数据与实验数据基本一致。%NaI detector has different energy responses to different gamma rays,To accurately measure the dose of gamma radiation, energy response of NaI detector needs to be compensated.The project utilizes the software of MCNP to simulate the NaI crystal′s ( size:Φ30 mm ×20 mm) energy responses under lead shield with different shapes and sizes.By comparing the standard deviations of different lead models, we select the lead shield with the fittest shape and size.According to the result of the simulation, NaI detector has best energy response while lead shield of thickness is 4 mm, hole of radius is 6.7 mm (20%exposure area) .Through experiment, theo-retical data were consistent with the experimental data.
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