SOFT X-RAY REFLECTIVITY AND THERMAL STABILITY OF CoCr/C MULTILAYER X-RAY MIRRORS

Abstract

The development of highly reflective multilayer mirrors for use in the wavelength region around 6 nm is desired for X-ray photoemission spectroscopy for inner-shell excitation using a Schwarzschild objective. For this application, reflectivity is the most critical parameter determining the performance of multilayer mirrors, because the reflectivity of multilayers in the 6 nm region is generally very low. We have designed CoCr/C multilayer mirrors with a comparatively high reflectivity at around normal incidence and have fabricated them by magnetron sputtering. The measured peak reflectivity is about 16% at a wavelength of around 6 nm and an incident angle of 88°. The reflectivity remains almost constant for 4 h under 300°C in an Ar atmosphere.