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Abstract：
The anisotropic emission of neutrons from a cylindrical X1 252Cf source with the spherical external casing was experimentally determined. The influence of metal materials and shapes of the external casing to the anisotropy factor, FI(θ), was assessed by the Monte Carlo calculation, before performing the measurement. The results of the calculation implied that light- and spherical-shaped external casing decreases the anisotropic emission of neutrons from a cylindrical source and the nature of the material does not affect the anisotropic emission to a large extent. The experimental results obtained when a spherical-shaped aluminum protection case was employed also revealed that the anisotropy factor was close to 1.0 with a wide zenith angle range. Considering the source handling and measures against mechanical impact to the source, we designed an SUS304-made spherical protection case for a renovated source delivering apparatus. With the SUS304-made spherical protection case, the measured anisotropy factor FI(90) was determined to be 1.002 ± 0.002 (k = 1). Results from the experiments also indicated that the measured anisotropy factor has a flat distribution from 55 to 125° with zenith angle.
摘要：
实验确定了具有球形外壳的圆柱形X1252Cf源的中子各向异性发射。金属材料和外壳形状对各向异性因素的影响,FI(θ),通过蒙特卡洛计算进行评估，在进行测量之前。计算结果表明，光形和球形外壳减少了来自圆柱源的中子各向异性发射，并且材料的性质不会在很大程度上影响各向异性发射。当采用球形铝保护外壳时获得的实验结果还表明，在宽的天顶角范围内，各向异性因子接近1.0。考虑到源的处理和对源的机械冲击措施。我们设计了一个SUS304球形保护箱，用于翻新的源输送设备。使用SUS304制成的球形保护外壳，测得的各向异性因子FI(90)确定为1.002±0.002(k=1)。实验结果还表明，测得的各向异性因子在天顶角为55至125°之间呈平坦分布。
