This paper details the development of a precise assembly of two supermirrors for neutron-focusing, designed for installation in neutron reflectometer SOFIA at BL16 in J-PARC MLF to intensify the illumination for small samples. The supermirrors are sputtered on two metal substrates, whose surfaces are coated with amorphous Ni-P plating, and are figured by diamond cutting and polished to subnanometer roughness. Special care is taken while polishing the substrates to reduce waviness and surface roughness for achieving a sharp focusing spot and uniform neutron reflectivity. The supermirror could converge the neutrons into a focal spot with a width of 0.13 mm in the full width at half maximum.

中文翻译：

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椭圆中子聚焦超镜，用于中子反射法中的小样品照明

本文详细介绍了用于中子聚焦的两个超级镜的精密组件的开发，该组件设计用于安装在J-PARC MLF中BL16的中子反射计SOFIA上，以增强小样本的照明。超级镜被溅射在两个金属基板上，其表面覆盖有非晶态的Ni-P镀层，并通过金刚石切割和抛光至亚纳米粗糙度进行图形化处理。在抛光基板时要格外小心，以减少波纹度和表面粗糙度，以实现清晰的聚焦点和均匀的中子反射率。超级反射镜可以将中子会聚成一个焦点，该焦点的最大宽度为整个最大宽度的0.13毫米。