Low- and intermediate-β, 352 MHz superconducting half-wave resonators for high power hadron acceleration

Two prototypes of superconducting, 352 MHz coaxial half-wave resonators with β=0.17 and β=0.31 have been designed, constructed, and tested at INFN-LNL, in the framework of the SPES and EURISOL DS projects. Main features of these double-wall, 2-gap structures are compactness, mechanical stability, and easy installation in different kinds of cryostats. Their acceleration capabilities are similar to the ones of Spoke resonators with similar β. These cavities are being developed for acceleration of high power hadron beams in the 5–100  MeV/u energy range.