A hybrid solid-state induction modulator with pulse transformer to drive SLAC klystrons

Abstract

A solid state hybrid induction modulator has been built and tested which can replace the line type modulators currently in use to power SLAC klystrons. The modulator uses twenty-two IGBT modules to drive eleven single turn primary windings of a transformer in parallel. Passing a pipe through the center of the vertically stacked METGLAS cores forms the single turn secondary. One end of the secondary winding is tied to ground, while at the output an induced voltage of eleven times the primary charge voltage is produced. The modulator in turn powers a conventional SLAC high voltage transformer and klystron. The output voltage produced by the "short stack" modulator built at SLAC is 24 kV, with a current of 6000 A. Pulse widths of np to 3 ps, at 120 Hz can he produced.Design details, test data, and comparisons with the conventional line type modulators will be presented.