Higher order mode damping studies on the PEP-II B-Factory RF cavity

The higher-order-mode (HOM) properties of the prototype 476 MHz RF cavity were studied for the proposed PEP-II B-Factory, and a waveguide damping scheme was proposed to reduce possible HOM-driven coupled-bunch beam instability growth. Numerical studies include modelling of the HOM spectrum using MAFIA and ARGUS, and calculation of the loaded Q's of the damped modes using data from these codes and the Kroll-Yu method. The experimental investigations of the modes are described which will be made in a full-size low-power test cavity, using probes, wire excitation and bead perturbation methods. (author) 14 refs.; 2 figs.; 2 tabs