Nested KB mirror fabrication for synchrotron hard x-ray nanofocusing

Abstract

Kirkpatrick-Baez (KB) mirrors consist of two individual mirrors: one vertical focusing mirror and one horizontal mirror at separate positions. Nested (Montel) KB mirrors consist of two mirrors arranged perpendicularly to each other and side-by-side. We report our results from the fabrication and tests of the first set of nested KB mirrors for a synchrotron hard x-ray micro/nano-focusing system. The elliptically shaped nested Platinum KB mirrors include two 40 mm long mirrors fabricated by depositing Platinum on Silicon substrates using the magnetron sputtering technique. Hard x-ray synchrotron tests have been performed at 15 keV and 2D focal spots of approximately 150 nm x 150 nm (FWHM) were achieved from both monochromatic and polychromatic beams at the 34 ID beamline of the Advanced Photon Source (APS) at Argonne National Laboratory. The side-by-side arrangement of nested KB mirrors requires them to have good surfaces and low figure errors at the intersection of the two mirrors' surfaces. It is very challenging to fabricate substrates that fit the nested KB mirror's arrangement and to deposit thin films to ideal elliptical shapes at the edge of the mirrors. Further research and development will be performed in the areas of fabrication and testing with respect to nested KB mirrors used in micro/nano-focusing systems. In particular, substrate processing and deposition techniques should be examined to improve the performance of the mirrors.