Design and tests of a gyrotron with a radially-extracted electron beam

A high-power gyrotron, employing an output coupling concept where the spent electron beam was extracted radially though a slot in the output waveguide, has been designed and tested. The separation of the collection area for the electron beam from the outgoing microwave power is required to achieve MW-level average power in gyrotrons. The tube employed a [TE.sub.22,2,1]-mode interaction cavity that was designed for operation at a frequency of 110 GHz. Tests on the tube resulted in an output power level of 470 kW for pulse durations of 2.5 seconds in the desired [TE.sub.22,2] mode at 110 GHz. Output power levels of 1 MW were achieved under short-pulse (1 ms) operation.