MUFFIN-TIN CAVITIES AT X-BAND FOR LINEAR-ACCELERATOR APPLICATION

A series of 2-cell, TT-mode, standing wave accelerator cavities operating at 8.6 GHz has been fabricated from thin (0.5 mm) Nb sheet metal. The cavities are of the rectangular geometry, muffin-tin variety. Of six cavities, four achieved effective accelerating fields greater than 17 MeV/m; the other two reached 11 and 14 MeV/m. The accelerating gradient in the best cavity was 21.8 MeV/m, corresponding to a peak rf magnetic field of 14009Gauss. Q values in all cases were greater than 1 x 10. No significant electronic activity was observed in any of these cavities. As*a preliminary undertaking, several 1-cell X-band cavities have also been fabricated using the same technology. Similar statistics for accelerating field values were obtained and the peak rf magnetic field achieved in the best 1-cell cavity was 1600 Gauss. A summary of the fabrication and preparation techniques together with test results are presented. © 1979 IEEE