Application of the spinning technique to the production of high beta seamless superconducting resonators for particle accelerators

Superconducting resonators for high beta particle accelerators are multicell structures made of niobium or of niobium-sputtered copper. In both cases the resonator bases are traditionally fabricated by spinning or deep drawing half-cells and electron-beam welding them together at the level of the equator; cells are then welded to one another at the level of the iris. Although after several years of research, this manufacturing procedure has become well-established both for niobium and for copper cavities, full-penetrating electron-beam welds increases production costs, and may easily jeopardize the quality of results in both cases. The authors have developed an original technique for the preparation of seamless 1.5 GHz cavities by simply lathe-spinning a planar disk or a seamless tube. Both niobium and copper can be easily manufactured with high reproducibility and significant savings in manufacture costs.<>