Fabrication of elliptical mirror at nanometer-level accuracy for hard x-ray focusing by numerically controlled plasma chemical vaporization machining

We established an efficient ultraprecise figuring process in which numerically controlled plasma chemical vaporization machining (NC-PCVM) and numerically controlled elastic emission machining (NC-EEM) are utilized serially. Intensity images of the x rays reflected by total reflection mirrors greatly fluctuate with respect to the figure error of spatial wavelength ranging from submillimeter to 10 mm. In NC-PCVM, figure errors for spatial wavelength range longer than 10 mm are removed efficiently by using the rotary electrode, and the spatial wavelength close to I mm can be corrected by using the pipe electrode. The residual figure error for the spatial wavelength close to 0.1 mm is finally removed by EEM. In this article, we describe the ultraprecise figuring process utilizing the NC-PCVM. Two elliptical mirrors for a Kirkpatrick-Baez (KB) microfocusing unit were manufactured by NC-PCVM using the rotary electrode and the pipe electrode in combination, and a figure accuracy higher than 3 nm (p-v) was achieved for the spatial wavelength range longer than I mm. The focusing properties of the two mirrors were evaluated at BL29XUL of SPring-8, and line focusing widths of 0.12 and 0.2 mum (full width at half maximum) were achieved at 15 keV. (C) 2003 American Institute of Physics.