基于蒙特卡罗方法的中子屏蔽材料设计

基于蒙特卡罗粒子输运程序MCNP，设计了一种强度高、密度低、具有优异中子屏蔽性能的新型玻璃纤维/B4C/环氧树脂复合材料，模拟计算了镅-铍（Am-Be）中子源产生中子对该材料的透射率；研究了该材料的中子屏蔽性能与传统屏蔽材料的差异以及不同B4C质量分数对该材料的屏蔽性能影响；根据模拟结果分析了该材料对不同能区中子（慢中子、中能中子、快中子）具有的不同屏蔽性能。研究发现：B4C质量分数为10%的该种新型玻璃纤维/B4C/环氧树脂复合材料的中子屏蔽性能，尤其是慢中子屏蔽性能较传统的含硼聚乙烯和Al-B4C合金材料更为优异；但随着B4C质量分数的增大，屏蔽性能提升不明显。结果验证了蒙特卡罗方法用于中子屏蔽材料优化设计的可行性。

Neutron shielding material design based on Monte Carlo simulation

Based on the Monte Carlo particle transport program MCNP, a novel glass fiber/B4C/epoxy resin composite for neutron shielding with high strength and low density was developed. Its neutron transmissivity was calculated under the Am-Be neutron source condition to study the difference of neutron shielding performance between the glass fiber/B4C/epoxy resin composite and traditional shielding materials. Furthermore, effects of B4C mass fraction of the composite on the shielding performance for neutrons with different energy(slow neutron, intermediate neutron, fast neutron) were analyzed. The results show the composites with 10% B4C mass contents have more advantages on the neutron shielding performance , especially the slow neutron shielding performance in comparison with polyethylene/boron containing composites and Al-B4C alloy. With the further increasing of the B4C contents, no remarkable increase is observed. Monte Carlo method is demonstrated feasible in optimization design of neutron shielding materials and the results provide a theoretical basis for design and preparation of a new neutron shielding composite.