The evaluation of a flat test piece of metal material for ellipsoidal neutron supermirrors

As a probe for measuring the inner structure of soft matter or metal materials, neutrons are unique and therefore very useful. However, to raise the efficiency of measurements which use focused neutron beams, a special optical device such as a super mirror, is required. Conventionally, the substrate for a neutron super mirror is made of polished quartz glass. In this research, we coated the surface of the substrate with electroless NiP and created a smooth surface with the roughness of 1.3 nm [rms] by ultrahigh precision cutting and 0.6 nm [rms] for mechanical polishing. We measured the reflectivity by using neutrons. (author)