Development of 700 pps high-duty-cycle line-type pulse modulator

High-duty-cycle line-type pulse modulator has been developed to drive 5.5 MW S-band klystron at 700 pps maximum repetition-rate and 14 mu sec flat-top pulse-width. To keep enough recovery time to thyratron-tube, the command charging scheme was adopted. To do this, a charging SCR-bank has been developed, which is capable of handling peak charging current of 50 A. The system achieved world wide highest average output-power of 205 kW. Two modulators have been installed in a new high-duty-cycle electron linear accelerator, which has been started its business operation in March 1996 as an electron-beam-sterilization facility.