Ion beam figuring for X-ray mirrors: history, state-of-the-art and future prospects

J Synchrotron Radiat. 2024 Jul 1. doi: 10.1107/S1600577524002935. Online ahead of print.

Abstract

Synchrotron light sources require X-ray optics with extremely demanding accuracy for the surface profile, with less than 100 nrad slope errors and sub-nanometre height errors. Such errors are challenging to achieve for aspheres using traditional polishing methods. However, post-polishing error correction can be performed using techniques such as ion beam figuring (IBF) to improve optics to the desired quality. This work presents a brief overview of the history of IBF, introduces some of the challenges for obtaining such demanding figure errors, and highlights the work done at several in-house IBF facilities at synchrotron light sources worldwide to obtain state-of-the-art optical quality.

Keywords: X-ray mirrors; X-ray optics; ion beam figuring; synchrotron radiation.