PROMISING PERFORMANCE OF THE Nb/Cu CLAD SEAMLESS SUPERCONDUCTING RF CAVITIES

For future large applications of superconducting RF cavities, one has to fabricate cost-effective cavities with high electric-field gradients. We have proposed the fabrication of L-band seamless cavities from Nb/Cu clad material in order to eliminate the electron beam welding process. A feasibility study on the fabrication of 1.3 GHz Nb/Cu Clad single cell cavities from the clad sheet material was done. Three single cell Nb/Cu clad seamless cavities were fabricated by the collaboration with INFNLNL in Italy. In this paper, cold test results of seamless type cavities obtained by the spinning method are presented. The best performance of the cavities was Eacc = 25.1 MV/m with Qo=2.5X10 10 at a temperature of 1.4 K, which is very promising.