A new surface treatment for niobium superconducting cavities

A condition necessary for the successful performance of superconducting cavities is the cleanliness of their inner surface. The firing of niobium cavities under vacuum at very high temperature is known to be a particularly effective method for cleaning the surface and for suppressing electron field emission. However, this process is inconvenient and expensive, if it is done in the “usual way”, i.e. in a high vacuum furnace. We propose an alternative technique for cavity firing, using local heating in an electron beam or laser welding facility. This treatment is easy, and can readily be integrated in the usual process of cavity production. Initial tests-at Saclay have given very promising results