34 GHz cusp gun driven peniotron

Summary form only given. A peniotron designed for optimum device efficiency is currently being assembled at UC Davis. The peniotron incorporates a four-vane slotted (magnetron-like) cavity operating in the fundamental waveguide mode, the /spl pi//2 mode. Interaction is at approximately 34 GHz with the second-harmonic beam mode. This interaction provides good separation from possible competing gyrotron modes. The cavity incorporates an output coupling iris which is required to achieve the desired loaded Q of 375 necessary for overcoupling of the device and optimum power output. The predicted output power is approximately 125 kW (at 47% device efficiency as predicted with our large-signal code). Cold test of the cavity/iris combination shows good agreement with predictions from simulation with HFSS. The interaction is powered by a Northrop-Grumman cusp gun which provides the high quality axis-encircling electron beam required for efficient interaction. For the device to operate as predicted, the gun will supply 3.5 amps at 70 kV. The spent beam should be suitable for recovery with a single-stage depressed collector, raising the total device efficiency to 57%.