A New SRF Cavity Processing Technique for the Elimination of Field Emission and Surface Preparation in Fully Assembled Cavities

73156S03- I Superconducting Radio Frequency (SRF) cavities are a critical device for present and future particle accelerators in military, research, and industrial applications. The performance of these cavities is limited by field emission, which is controlled by cavity processing techniques. However, currently available processing techniques provide less-than-satisfactory cavity performance, are expensive, and use dangerous wet chemistry. This project will develop a technique for the more complete removal of particulates, which are responsible for field emission in the SRF cavities. The technique, which uses reactive ion etching combined with electrostatic precipitation, also will allow for the control of the cavity surface chemistry and will eliminate the use of aggressive acids in the cavity processing. Phase I will develop a set of tools to investigate process variables, demonstrate the effectiveness of particulate removal, and characterize the surface chemistry on samples in a cavity geometry. Field emission mapping of the samples, etch rates, and depth profiling will be used as measures of process outcomes. Commercial Applications and Other Benefits as described by awardee: Particle accelerators are an integral part of basic research in high energy, nuclear, and biological sciences as well as for military and industrial applications. Improvements in SRF cavity performance and cost should increase their application by providing more cost effective solutions in all these areas.