High power operation of an<i>X</i>-band gyrotwistron

Abstract

We report the first experimental verification of a gyrotwistron amplifier. The device utilized a single 9.858 GHz, ${\mathrm{TE}}_{011}$ cavity, a heavily attenuated drift tube, and a long tapered output waveguide section. With a 440 kV, 200-245 A, 1 \ensuremath{\mu}s electron beam and a sharply tapered axial magnetic field, peak powers above 21 MW were achieved with a gain near 24 dB. Performance was limited by competition from a fundamental ${\mathrm{TE}}_{11}$ mode. A multimode code was developed to analyze this system, and simulations were in good agreement with the experiment.