中子照相数值模拟与实验的对比

 介绍了热中子照相的MCNP数值模拟方法，模拟了300＃反应堆Maxwell谱热中子束穿透样品射到转换屏的过程，给出了热中子对铝、铅、铁、铜的穿透能力，分析了引起模拟与实验结果不同的原因。通过模拟得到了清晰的图像，对比数值模拟与在300#反应堆中子照相装置上的实验结果，数值模拟结果图像与实验结果图像非常相似；散射中子对图像的影响也符合相同的规律，随着样品与转换屏之间的距离的增大，散射中子对结果图像的影响越来越小，当样品与转换屏之间的距离为样品尺寸的2倍时可以忽略散射中子的影响。

Simulation and experiment of neutron radiography

MCNP simulation method of neutron radiography is introduced.The process that Maxwell thermal neutron penetrates the samples is simulated,and clear images are obtained.The contrast of simulation results and actual neutron radiography is also given.The simulation images are very similar to the experimental images.The analyse of the effect of scattered neutrons is included.As the distance between objects and scintillation screen increases,the scattered component decreases.For a distance of double object size,the influence of the scattered neutrons to the image can be ignored.The ability that thermal neutrons penetrates Al,Pb,Fe and Cu is discussed.The reason for the difference between simulation and experimental results is studied.The conclusion can be drawn that the MCNP simulation method of the neutron radiography is credible and can be used to supervise neutron radiography investigation.