Evaluation of Surface Roughness of Quartz Glass Substrate in Fabrication Process for Neutron Focusing Mirror
The aspherical supermirror is among the most useful optics for focusing a neutron beam with a wide wavelength range. The improvement in surface roughness is essential for increasing the focusing gain. A highly efficient and high-precision fabrication process for the substrate of the aspherical mirror combining conventional precision grinding, numerically controlled local wet etching (NC-LWE) figuring, and low-pressure polishing was developed. Using this new fabrication process, plano-elliptical neutron-focusing mirror substrates were successfully fabricated with a figure error of submicrometer order and an rms surface roughness of less than 0.3 nm. In this report, the surface roughness of a quartz glass substrate for a neutron focusing supermirror was evaluated.
M. Nagano et al., "Evaluation of Surface Roughness of Quartz Glass Substrate in Fabrication Process for Neutron Focusing Mirror", Advanced Materials Research, Vol. 325, pp. 647-652, 2011