Large orbit gyroklystron development at Los Alamos

The authors have designed and are testing a large orbit gyroklystron amplifier for 1.3 GHz operation in 65 ns pulses. The ultimate power output goal is 500 MW with a gain in excess of 20 dB. This initial investigation is intended to lay the groundwork for operation at 11.4 GHz for particle accelerator applications, and also at frequencies of up to 35 GHz for other uses. Computational design has been performed with the resonant cavity code MAFIA and the particle in cell codes MERLIN and ISIS. Electron beam optics through a magnetic cusp was also studied with ISIS and MERLIN, and verified experimentally, to develop a suitable electron beam trajectory from the diode into the resonator region. Performance tests of a single stage device have been performed. An unsaturated gain of 43 dB has been observed using 4 kW of input drive, yielding an amplified output of 100 MW