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模拟了14MeV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(496nm)光子数在模拟实验中,分析了影响图像质量的因素。首先计算了散射中子本底与闪烁体和样品(聚乙烯)间距的关系。当间距为厘米量级时散射中子本底对图像的影响很小。其次,计算表明系统对样品的甄别厚度与入射中子总数N有关,在一定范围内近似与logN成线性关系。最后,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。
The effect of 14MeV neutrons on scintillator fibers after their penetration through the sample was simulated. The energy deposition in each fiber was calculated and converted to a visible light (496 nm) photon number. In simulation experiments, the factors affecting the image quality were analyzed. First, the relationship between the scattering neutron background and the distance between the scintillator and the sample (polyethylene) is calculated. Scattering neutron background has little effect on the image when the pitch is on the order of centimeters. Secondly, the calculation shows that the screening thickness of the sample is related to the total number of incident neutrons N, and it is approximately linear with logN within a certain range. Finally, the plane resolution of the system under the condition of ideal parallel neutron beam incident is given through the simulation results.