Parasitic resonance in a solid-state pulsed power modulator

A resonant structure, induced by parasitic capacitance and inductance, was studied in a solid state pulsed power modulator for an induction synchrotron. Parasitic capacitors form a resonant structure in a switching arm with a self-inductance of the modulator circuit. The resonance induces a ringing in an acceleration voltage, causing an extra force to particles in the longitudinal direction. This effect is serious around the transition energy, because a mismatch exists between the particle distribution before the transition and a bucket shape after the transition. It was found that the most promising way to avoid this situation is to reduce the self-inductance of the modulator circuit. By sufficient reduction, an output waveform without any serious deterioration of flatness has been achieved by a newly developed power modulator.