DESIGN AND CHARACTERIZATION OF THE POWER COUPLER LINE FOR HIE-ISOLDE HIGH BETA CAVITY

The design parameters of the HIE-ISOLDE high beta superconducting (SC) cavity foresee to have a power dissipated on the cavity wall of 7W with a Q0=6.6·108 for an accelerating field of 6MV/m. The cavity will be fed via a moveable antenna that, in operating condition, is designed to reach a maximum overcoupled condition β=130 in order to get a bandwidth at the resonant frequency of ≈20Hz. A wide dynamic range (Qext ranging from 104 to 109) is requested in order to allow tests and conditioning both at room temperature and in superconducting operating mode. A “dust free” sliding mechanism has been integrated in the mechanical concept which will be presented below together the full e-m analysis of the coupler line.