Polished diamond x-ray lenses

TL;DR

This paper demonstrates high-quality bi-concave diamond x-ray lenses with improved surface polishing, showing comparable focusing performance to beryllium lenses but with lower small-angle x-ray scattering, indicating potentially better beam quality.

Contribution

It introduces polished diamond x-ray lenses with figure errors similar to commercial beryllium lenses and compares their performance and scattering properties.

Findings

Polished diamond lenses have similar figure errors to Be lenses.

Diamond lenses produce comparable beam focus sizes.

Lower SAXS signals indicate reduced scattering in diamond lenses.

Abstract

We present high quality bi-concave 2D focusing diamond x-ray lenses of apex-radius $R=100~\mu$m produced via laser-ablation and improved via a mechanical polishing process. Both for polished and unpolished individual lenses and for stacks of 10 lenses, we show the remaining figure errors determined using x-ray speckle tracking and compare these results to those of commercial $R=50~\mu$m beryllium lenses that have similar focusing strength and physical aperture. For two stacks of 10 diamond lenses (polished and unpolished) and a stack of 11 beryllium lenses, we present measured 2D beam profiles out of focus and wire scans to obtain the beam size in the focal plane. These results are complemented with small angle x-ray scattering (SAXS) measurements of a polished and an unpolished diamond lens. Again, we compare this to the SAXS of a beryllium lens. The polished x-ray lenses show similar figure errors to commercially available Be lenses. While the beam size in the focal plane is comparable with that of the Be lenses, the SAXS signal of the polished diamond lenses is considerably lower.