High stabilization of an output of a submillimeter wave gyrotron

Summary form only given, as follows. High frequency, medium power gyrotrons (Gyrotron FU series) have been developed in Fukui University as radiation sources covering a broad band from millimeter to submillimeter wave region. We have performed cw operation of the Gyrotron FU IV. The fluctuations of the cathode potential and the anode potential result in fluctuations of the output power and frequency. These were stabilized by decreasing the fluctuations of the potentials via introducing smoothing circuits consisting of a resistor, an induction coil and a capacitor. Further stabilization of output frequency was attained by applying phase lock loop.