Green Electropolishing for Niobium SRF Cavities

The ability of nuclear physics research to continue to make a significant impact on the scientific community relies on advances in accelerator performance, particularly on improvements in superconducting radio frequency (SRF) cavities. In order to obtain optimal performance, the inner surfaces of the SRF cavities must be clean, smooth, and free of damage. However, current methods of treating the surfaces of SRF cavities use a chemical etch or an electropolish, both of which were developed about 35 years ago and both of which use extremely hazardous hydrofluoric acid. This project will develop an environmentally-benign, low-cost, effective surface treatment for SRF cavities. Commercial Applications and other Benefits as described by the awardee: The new surface treatment will reduce the environmental impact of electropolishing and eliminate the need for an energy-consuming (~800 ºC) hydrogen degassing anneal. SRF cavities are used in many areas of nuclear and high-energy physics research, as well as for medium and low energy particle accelerators and Free Electron Lasers. These accelerators have potential applications in industrial processing, medical diagnostics, pharmaceutical research, and weapons systems.