基于MCNP对γ射线吸收剂量累积因子的计算与研究

使用蒙特卡罗程序MCNP计算了常用材料下的吸收剂量累积因子,计算时采用了较新的截面数据库MCPLIB04及介质材料的衰减参数数据库,并考虑了轫致辐射和相干散射等物理过程,同时将计算结果与相关文献给出的数据进行了比较,分析了造成差异的主要原因。结果表明:利用MCNP计算出的低Z材料的吸收剂量累积因子值在入射光子的中能区部分,平均比文献给出的数据偏小,在高能区部分平均比其偏大;而利用MCNP计算出的高Z材料的吸收剂量累积因子则普遍比文献给出的数据偏大。本文工作可为更新目前使用的较为陈旧的累积因子数据库提供参考。

Research on gamma ray buildup factor for energy absorption based on MCNP

Energy absorption buildup factors of common materials were calculated using the Monte Carlo simulation code MCNP.In the calculations,the newer cross section library (MCPLIB04) and mass energy coefficients of common materials have been used with consideration of the bremsstrahlung and correlative scatter.The results were compared with the reference data and the differences were analyzed.It showed that,for the low -Z materials,the values of buildup factors calculated by MCNP were averagely smaller than the reference data for the intermediate γenergies,whilst the calculated values were averagely bigger than the reference data for the high γ energies.For high-Z materials,the calculated results of buildup factors were generally bigger than the reference data.This work could provide updated data for the old buildup factors.