Purity of Nb and Pb films deposited by an ultrahigh vacuum cathodic arc

This paper reports on recent progress in the application of ultrahigh vacuum arc technology, which was proposed as an alternative solution for the deposition of thin superconducting films of pure niobium upon the inner surfaces of RF cavities designed for particle accelerators. New experiments were conducted to deposit superconducting films of pure niobium and lead needed for the modern accelerator technology. Presented scanning electron microscopy, scattered ion mass spectroscopy technique, and glow discharge-optical emission spectroscopy studies of such produced Nb and Pb films showed that the concentration level of impurities is lower than 0.2% and 1%, respectively. Achieved cleanliness goes together with outstanding superconducting properties. The main experimental results and characteristics of arc-deposited thin superconducting films are discussed, and the progress achieved recently in the formation of such films is presented.