Operating characteristics of a 35GHz gyromonotron

Results of experiments on the characteristics of a single cavity gyrotron oscillator are presented. The device produces 150 KW, has an efficiency of 31% and a pulse length of 10 msec. The linewidth of the emitted radiation appears to be limited by the droop in the power supply, and was measured to be 1.5 MHz. A tapered cavity is used in the oscillator. Calculations of the device efficiency which assume fields measured in the cavity in the absence of the beam are in excellent agreement with experimental observations. Experiments on the effect of tapering the applied magnetic field are also presented. Theory predicts efficiencies on the order of 50% for these experiments.