Large-Scale Industrial Production of Superconducting Cavities

Many laboratories around the world, notably CEBAF, CERN, DESY and KEK, after a period of research and development, are presently or have recently been involved in the industrial production of a large number of RF superconducting cavities. CERN, instead of using the standard bulk niobium technique, has developed a new Nb/Cu technology (niobium film deposited by magnetron sputtering on copper). The aim of this paper is to present the transfer of this technology to three European firms [Ansaldo, CERCA and Siemens (now ACCEL)]. Emphasis will be placed on the major challenges to industry of mastering the very complex procedure (which requires high quality control at every stage of the production) needed to achieve a very demanding final RF performance [Q(6 MV/m) = 3.4¥109 at 4.5 K].