MCNP5模拟γ能谱与吸收介质的相关性

Correlation of Gamma Energy Spectrum and Absorbing Medium With MCNP5

为了研究γ能谱与吸收介质的原子序数、密度及其厚度之间的关系,基于蒙特卡罗方法,应用MCNP5程序模拟40K发出的能量为1.46MeV的γ射线穿过12C2、7Al3、2S5、6Fe6、5Zn等吸收介质板后γ能谱的变化,归纳总结了γ能谱与吸收介质参数的相关性。模拟实验结果显示,吸收介质的原子序数对γ能谱低能部分影响较大,随着原子序数的增加低能峰峰高逐渐降低,同时峰位有向高能部分移动的趋势;介质密度和厚度都不会改变γ能谱峰位,只是改变谱峰高度和康普顿坪;随着介质密度的增加,γ能谱峰高和康普顿坪逐渐降低;吸收介质厚度变大时,低能峰峰高和康普顿坪有逐渐变高的趋势。

In order to research on the correlation of gamma energy spectrum and absorbing medium,based on the method of Monte Carlo,MCNP5 was used to simulate the changes of gamma energy spectrum after gamma photons for 1.46 MeV eitted by 40K through absorbing mediums on 12C,27Al,32S,56Fe and 65Zn,and summarizes the relationship between the characteristics of gamma energy spectrum and the atomic number,the density and thickness of the materials.The results showed that the atomic number of absorbing medium has great influence on low-energy parts of gamma energy spectrum.With increasing atomic number,low-energy peak height gradually decrease,and peak position moves to higher-energy direction.Both medium density and thickness didn＇t change peak position of gamma energy spectrum except peak height and Compton plateau.Peak height and Compton plateau of gamma energy spectrum decrease gradually with increasing medium density.When the thickness of absorbing medium increased,low-energy peak height and Compton plateau gradually were changed to higher.