Beam loading effects in the APS booster

Beam loading of the radio-frequency (rf) accelerating cavities is an important consideration in the design and operation of high-current circular particle accelerators and storage rings. The steady-state and transient perturbations of the rf cavity system by the circulating beam can be harmful to the beam and limit the accelerator performance. Transient beam loading effects have been observed soon after injection of the beam into the booster synchrotron of the Advanced Photon Source (APS). Data are presented quantifying the responses of both the beam and the rf cavities to beam loading under various conditions. A preliminary discussion addresses the compensation of these beam loading effects. 3 refs., 3 figs., 1 tab