铝基碳化硼材料中子屏蔽性能的蒙特卡罗模拟

采用蒙特卡罗方法, 运用MCNP4C程序研究了碳化硼含量20%–40%、中子能量200 eV–15 keV、材料厚度0.3–2 cm对B₄C/Al复合材料中子屏蔽性能的影响. 结果表明: 碳化硼含量与中子透射系数呈一次线性下降关系; 同含量的碳化硼, B₄C/Al材料的中子屏蔽效果要大大优于聚乙烯碳化硼材料; 在等厚度条件下, 模拟试样B20等的中子屏蔽效果要优于水、铜、混凝土等常规屏蔽材料; 材料厚度与中子透射系数呈指数下降关系, 且单位厚度的增加对中子透射系数改变很大; 含硼量对热中子透射系数影响很大; 在热中子能区, 中子每单位能量的变化对中子透射系数改变较大; 在慢中子能区, 中子每单位能量的变化对中子透射系数改变很小.关键词：中子透射系数蒙特卡罗铝基复合材料碳化硼

The Monte Carlo simulation of neutron shielding performance of boron carbide reinforced with aluminum composites

Three groups of neutron shielding experiments were set up to study the shielding performance of B₄C/Al composite, using the Monte-Carlo method. We have made the following changes: the content of boron carbide 20%–40%, neutron energy 200 eV–15 keV, material thickness 0.3–2 cm, so that we can draw the conclusions: the content of boron carbide and neutron transmission coefficient show a linear relation, with a big drop; under the same neutron energy, the neutron-shielding qualities of simulated specimens are for better than polyethylene boron carbide at the same content of B₄C and water, copper, and concrete at the same thickness; an exponential decline relationship is exhibited by material thickness and neutron transmission coefficient, which change greatly with the increase in unit material thickness; the content of boron affects the thermal neutron transmission coefficient seriously. In the thermal neutron energy region, the change of per unit neutron energy(100 eV) has a big influence on neutron transmission coefficient. In the slow neutron energy region, the influence is small.
Keywords：neutron transmission coefficientMonte-Carlo methodaluminum matrix composite materialboron carbide