Fabrication of ultrashort X-ray focusing mirrors by differential deposition method

Abstract

Our ultrashort Kirkpatrick-Baez mirror with 2- and 8-mm-long mirrors has an extremely short focal length of 2 mm. While its working distance is also shortened, this design can benefit microscopic observation and X-ray focusing. Compared to the conventional X-ray mirrors whose radii of curvature typically exceed 10 m, these ultrashort mirrors have steeply curved figures with a radius of curvature of 150 mm. This presentation shows the fabrication results of these ultrashort mirrors. Their measurement employed a scanning white-light interferometer. A differential deposition method successfully transformed a concave cylindrical shape into an elliptical cylinder, resulting in a figure error of less than 20 nm in peak-to-valley.