Stabilization and modulation of the output power of submillimeter wave gyrotron

High frequency, medium power gyrotrons (Gyrotron FU series) have been devel oped at the Fukui University as radiation sources convering a broad frequen cy band from millimeter to submillimeter wave region. We have performed cw operation of the Gyrotron FU IV. However, the output power was not stable ( approximately several tens %) due to the fluctuation of the cathode potenti al (similar to 40 V). The output power was stabilized within several percen t by controlling the anode potential. Such a technique was also used for am plitude modulation of the gyrotron output. Improved stabilization of output power and effective modulation will be achieved by stabilizing the cathode potential. (C) 2001 Elsevier Science B.V. All rights reserved.