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, F_I(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 F_I(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.

中文翻译：

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用球形保护盒实验测定252CF中子源中子的各向异性发射。

实验确定了具有球形外壳的圆柱形X1 ²⁵² Cf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子F _I（θ），然后再通过蒙特卡洛计算进行评估。计算结果表明，轻型和球形外壳降低了来自圆柱形源的中子的各向异性发射，并且材料的性质在很大程度上不会影响各向异性发射。当采用球形铝质保护壳时获得的实验结果还表明，在宽天顶角范围内，各向异性系数接近1.0。考虑到放射源的处理方式和对放射源的机械冲击的措施，我们设计了一种由SUS304制造的球形保护盒，用于经过翻新的放射源传送装置。使用SUS304制成的球形保护盒，测得的各向异性因子F _I（90）被确定为1.002±0.002（k  = 1）。实验结果还表明，测得的各向异性系数在55至125°的天顶角处具有平坦分布。