Performance prediction and measurement of silicon pore optics

Abstract

We present the latest results of X-ray metrology performed on Silicon Pore Optics, a novel type of lightweight X-ray optics made from silicon and developed for future, large area space based X-ray telescopes. From these so-called pencil beam measurements, performed at the PTB laboratory of the BESSY synchrotron radiation facility, the overall performance in terms of half energy width (HEW) of the optics has been calculated. All measurements are performed at an intrafocal distance, but due to the nature of this measurement method, the results in terms of HEW can be extrapolated to the focal plane. In the near future, upgrades of the X-ray facilities will allow measuring the performance of the optics in the actual focal plane. We also present the newest development of our X-ray tracer tool, which is used to retrieve performance and imaging prediction from single plate level up to a full optic by use of the mirror figure, as recorded during the fabrication process. We furthermore present results of AFM imaging and X-ray reflectivity measurements performed to determine the surface roughness of the base material (polished Si wafers) and of fully processed and coated mirror plates.