Design, performance, and utilization of the Low-Energy X-ray Reflectometer at DTU space

Abstract

A state-of-the-art compact Low-Energy X-ray Reflectometer is in operation at DTU Space and is used to characterize x-ray coatings for the optics of future spaceborne and ground-based telescopes. The reflectometer is housed in a vacuum chamber and operates at 1.487 keV, complimenting an existing 8.048 keV reflectometer. With a microfocus source and plane-parabolic Kirkpatrick–Baez mirrors, the 0.5-mm wide beam is collimated to <0.75 arcmin. An actively cooled 2D CCD yields sample alignment precision of 26 μm in linear position and 0.18 arcmin in angle. A multilayer monochromator provides a peak reflectance of 43.5% and beam purity > 99 % . The reflectometer has a 2θ range of 0 deg to 35 deg and dynamic range up to eight orders of magnitude. Techniques are demonstrated to investigate the sample surface morphology and we show the system’s capability to detect the presence of atmospheric contaminants on coated mirrors.