【摘要】 利用蒙特卡罗模拟程序MCNP研究了NaI(Tl)探测器对海水中137Cs、131I的比计数率响应情况;计算了NaI(Tl)探测器对不同半径海水球体源中137 Cs与131I的比计数率响应曲线;分析了探测器防水套筒、NaI(Tl)晶体尺寸与结构、射线能量等因素对比计数率响应的影响;拟合了3R3型、5R5型NaI(Tl)探测器最大比计数率ymax及有效探测距离D。防水套筒模型与裸晶体简化模型的计算结果对比表明,裸晶体模型会给计算带来明显的偏差,应在模型设计时,考虑探测器结构,构建更精确的模型。更多还原

【Abstract】 A NaI(Tl)detector with waterproof sleeve used for in-situ measurement of specific activity of artificial radionuclides of 137 Cs and 131 I in seawater was modeled with MCNP,and the specific counting rate curves of the detector with and without waterproof sleeve were calculated with different source radii.The effects of the detector structure,the size of the NaI(Tl)crystal,and theγ-ray energy were investigated.The maximum specific counting rate and effective detection range were calculated and compared for the detectors of 3×3inches and 5×5inches with and without waterproof sleeve,and the results show that the simplified naked crystal model would bring more deviation from the true results.更多还原