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

• Published in: Journal of synchrotron radiation Vol. 31; no. 4; pp. 655 - 669
• Main Authors: Shurvinton, Riley, Wang, Hongchang, Pradhan, Paresh, Nistea, Ioana-Theodora, Alcock, Simon, Bazan Da Silva, Murilo, Majhi, Arindam, Sawhney, Kawal
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.07.2024; John Wiley & Sons, Inc
• Subjects: Error correction; Geometrical optics; ion beam figuring; Ion beams; Light sources; Polishing; synchrotron radiation; X‐ray mirrors; X‐ray optics; X-ray mirrors; synchrotron radiation; X-ray optics; ion beam figuring
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S1600577524002935

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. A review of the history of ion beam figuring and current developments is presented, with a focus on the production of high‐quality X‐ray optics.