Design and testing of power supplies for the high power gyrotron

The authors report on the design and test results of the JAERI gyrotron test facility at Naka which was originally intended for testing the high-power klystron. The AC GTO (gate turn-off thyristor) switch, the series regulator tube, and the high-speed protection system are applied for the power supply system. The AC GTO switch is able to break the current of 4500 A without any damaging surge voltage. The switch is also able to control the DC output voltage within ±5% at the cathode voltage of the regulator tube. The series regulator tube system is able to rise within 200 μs and keeps the flat-top voltage within ±0.13% at the cathode voltage of -80 kV for 1 ms. The high-speed interlock system realizes turn-off performance of 6 μs and a reliable and safe operation of the gyrotron. The authors have demonstrated the operation of 440 kW during 1 ms using a short pulse gyrotron at 120 GHz