Outgassing rate measurement of copper plated stainless steel

Stainless steel (SS) and Copper are very suitable structural metals for fabrication of UHV vessels. INDUS-1 is an electron storage ring, with 450 MeV electron energy. A new Radio Frequency (RF) cavity was fabricated for INDUS-1, with copper plating on SS. The main factor deciding the vacuum compatibility of the surface is the specific outgassing rate at room temperature as well as at the operating temperature. Surface properties are extremely important in this case. i.e., surface finish should be maintained without any blisters and micro cracks, after baking. In order to evaluate these factors, one sample was prepared (SS pipe plated with copper) and tested with simulated conditions in UHV environment. This paper gives the details of the experiments and the results on specific outgassing rate of the copper plated SS sample in different conditions, namely, at room temperature and after baking at different temperatures.