First Acceleration with Superconducting RF Cavities at ISAC-II

We have demonstrated the first acceleration of ions with superconducting rf at TRIUMF/ISAC. Alpha particles from a radioactive source are accelerated from 2.8 MeV through the ISAC-II medium beta cryomodule to a maximum energy of 9.4 MeV. The four 106 MHz quarter wave cavities (βo= 7%) are set to the ISAC-II specified gradient of 6 MV/m (Leff= 18 cm, Ep=30 MV/m and Veff=1.08 MV) with a cavity power of about 7 W per cavity. The final particle energy spectra is measured with a silicon detector. The experimental set-up including details of the source and diagnostic boxes and the detector electronics are described. Beam simulations of the unbunched, uncollimated beam indicate a unique spectral fingerprint that can be used to unambiguously determine each cavity voltage.