Transient Generation of Short Pulses in the APS Storage Ring

A method for obtaining very short pulses using modulation of the accelerating voltage gradient is described and simulation results are given. The idea is to operate the two rf stations with a phase separation adjusted so that the synchronous particle resides on the crest of one of the sources. Phase modulation of the on-crest system at twice the synchrotron frequency induces a longitudinal bunch shape oscillation with significantly reduced bunch length occurring twice each synchrotron period.