Design parameters of a high-efficiency 1.7-GHz gyropeniotron amplifier

The feasibility of the gyropeniotron amplifier as a high-efficiency, high-power RF source to act as driver for accelerators in the 0.8-1.7-GHz frequency range is discussed. The klystrode is difficult to operate in this frequency range. Design parameters are given for a 1.7-GHz gyropeniotron operating with an axis-encircling beam (100 keV, 10 A) in a magnetron-type slotted waveguide. The external magnetic field required is 326 G. The calculated efficiency for second cyclotron harmonic operation is 78 percent with a cold beam and 66 percent with a beam having 2 percent axial velocity spread and 5 percent guiding center spread. The depressed collector technique can easily be applied to enhance the efficiency since the spent beam in a gyropeniotron has little velocity spread.