Evaluation of cleaning process

The goal of the deliverable D15.1 is to define an optimum cleaning and polishing procedure for the surface preparation of Cu in order to minimize the substrate effect on the final properties of Nb film coating. The optimum cleaning and polishing process is defined through the evaluation of the superconductive properties of Nb thin film coated on Cu  planar samples that are cleaned and polished with different procedures. In this framework five different procedures were investigated for a total amount of 50 samples prepared. Nb thin film deposition was done on each sample using the same procedure and parameters. Several surface and superconductive characterisations were performed to evaluate the effect of the surface preparation on Nb film properties. Based on the results of the WP15 first year work, we concluded that the samples for task 15.3, will be prepared by 2 techniques only: electropolishing (EP), as a pitting free technique, and chemical polishing
(SUBU), as the techniques which provides the lowest roughness without scratches.