Laser polishing for topography management of accelerator cavity surfaces

Improved energy efficiency and reduced cost are greatly desired for advanced particle accelerators. Progress toward these goals can be made by atomically‐smoothing the interior surface of the niobium superconducting radiofrequency (SRF) accelerator cavities at the heart of these machines. Laser polishing offers a green alternative to the present aggressive chemical processes. We found parameters suitable for polishing niobium in all surface conditions that are expected for cavity production. Careful measurement of the resulting surface chemistry revealed a modest thinning of the surface oxide layer, but no contamination.