不同材料对γ射线衰减系数的MCNP模拟

Different Materials for γ-ray Attenuation Coefficient of MCNP Simulation

线衰减系数是研究材料屏蔽性能的重要参数。为了研究防辐射材料的线衰减系数，基于蒙特卡罗方法，运用MCNP程序模拟不同厚度、不同材料、不同组分材料对γ射线的线衰减系数，进而对材料的线衰减系数做了精确的计算，分析了几种材料的能谱图。同时建立了屏蔽材料的衰减系数-能量拟合方程，并分析了误差。模拟计算结果表明：相同能量下，不同厚度的同种材料线衰减系数相同；线衰减系数跟原子序数Z、材料的密度、组成成分有关；在0．02～1 MeV能量区间，几种材料的线衰减系数都是随着能量的增加而减小；PbO-B2 O3玻璃系统中，随着PbO含量的增加，其线衰减系数也增大。

Linear attenuation coefficient is important parameters in the study of the materials shielding perform -ance.In order to study the linear attenuation coefficient of the radiation protective material shielding , based on the Monte Carlo method , the MCNP program is used to simulate the linear attenuation coefficient of gamma rays of different thickness、different materials、different components of material .And precise calculations of material linear attenuation coefficient are carried out , the energy spectrum of several materials is analyzed .Also the line-ar attenuation coefficient -energy fitting equation of shielding materials is established , with the error analysed . Simulation results show that：under the same energy , same material has the same linear attenuation coefficient with different thickness;linear attenuation coefficient is associated with atomic number Z , the density of materi-al and composition of materials;In the energy range of 0.02~1 keV, with the increase of source energy E , lin-ear attenuation coefficient of several materials shows the tendency of decreases .In the PbO-B2 O3 glass system , with the increase of the content of PbO , the linear attenuation coefficient is also increased .