数值模拟高能中子照相

 模拟了14 MeV中子在穿透样品后与闪烁体光纤的作用。对每根光纤中的能量沉积进行了计算，并转换成可见光(496 nm)光子数。在模拟实验中，分析了影响图像质量的因素。计算了散射中子本底与闪烁体和样品(聚乙烯)间距的关系。当间距为cm量级时，散射中子本底对图像的影响很小。计算表明系统对样品的甄别厚度与入射中子总数有关，在一定范围内近似与中子总数的对数成线性关系。通过模拟结果给出了理想平行中子束入射情况下系统的平面分辨率。

Numerical simulation of high energy neutron radiography

In this paper,the simulation of interaction between scintillation fibers and 14 MeV neutrons after penetrating through objects is presented.The neutron radiation is converted to green light(496 nm) in scintillation fibers,and the number of photons in each fiber is calculated.In simulated experiments,factors influencing quality of images are analyzed.The variation of the number of scattered neutrons into the scintillator with the distance between objects and the scintillator is calculated,and the results indicate that,for a distance value of several centimeters,the influence of scattered neutrons to the image can be ignored.The simulation also indicates that for a certain range of the number of incident neutrons,the threshold thickness of objects which can be discriminated is approximately linear to the logarithm of the number.When incident neutrons are ideally parallel,the resolution of the system is approximately 0.5 mm.