Efficient Ka-band second-harmonic slotted peniotron

A harmonic peniotron has been designed for high efficiency and relative immunity to mode competition from gyrotron interactions. The device employs a 70-kV, 3.5-A, axis-encircling electron beam. To ensure stability from competing gyrotron interactions, the peniotron will operates in the lowest-order mode of a slotted four-vane circuit, the /spl pi//2-mode. The cavity is strongly diffraction coupled for a high circuit efficiency. The 33-GHz, slotted second-harmonic peniotron is predicted to yield 125 kW with an electron efficiency of 58% and a device efficiency of 52%. The device is being constructed at the University of California at Davis and is driven by a recently developed Northrop Grumman (Rolling Meadows, IL) cusp electron gun.