PLASMA TREATMENT OF SINGLE-CELL NIOBIUM SRF CAVITIES

In our previouswork, we have demonstrated on flat samples that plasma etching in Ar/Cl2 of bulk Nb is a viable alternative surface preparation technique to BCP and EP methods, with comparable etching rates. Here we reporton the progress in experimental design for plasma processing of a single cell SRF cavity. The experiments are centered on two discharge types - asymmetric RF and low mode microwave cavity discharge. We report on the experimental design of the setup with a specially designed single cell cavity with sample holders, and discuss the diagnostics of plasma and samples. We provide preliminary results on the RF discharge in the single cell that is to be the main part of the optimized experiment.