Introduction of Three-Stage Cavity Resonator in a Multi-Frequency Sub-THz Gyrotron

A multi-frequency gyrotron which has a multi-stage cavity resonator has been studied. So far, super multi-frequency oscillation was realized with a resonator consisting of two cavities with different diameters. Each cavity has a series of oscillation modes, which can be selected by the cyclotron frequency of the injected helical electron beam. In the present study, a three-stage-resonator is introduced to increase the number of operating frequencies. The oscillation experiments have shown that threestage resonator can be operated at more frequencies than the two-stage resonator.