Deposition of lead thin films used as photo-cathodes by means of cathodic arc under UHV conditions

The cathodic arc technology has been used for various technical purposes for many years. Recently, it has been demonstrated that the cathodic arc can be operated under ultra-high vacuum (UHV) conditions and it might solve the problem of the oxygen contamination coming from water remnants. It opens a new road to many applications where very pure metallic and/or superconducting films are needed. The paper reports on recent experimental studies aimed at the deposition of superconducting films of pure lead (Pb) by means of the UHV cathodic arc. Such layers can be used as photo-cathodes needed for modern accelerator injectors. The system configuration, used for thin film deposition inside the 1.3 GHz RF Gun designed at DESY, is described. The paper presents also the main results of Pb-films measurements, which were performed by means of SEM, SIMS and GD-OES techniques.