Harmonic results of a 460 GHz gyrotron

We report the first results of a 460 GHz second harmonic gyrotron. In microsecond pulse length operation at 13 kV and 110 mA, power levels in the order of 1 W have been observed at the TE/sub 2,6/ mode at 456.2 GHz and the TE/sub 0,6/ mode at 458.6 GHz. Modes at the fundamental, including the TE/sub 0,3/ at 238 GHz and the TE/sub 2,3/ at 233 GHz, have output powers up to 70 W. The TE/sub 5,2/ mode was observed to tune continuously in frequency from 246 GHz to 248 GHz. The gyrotron is being processed for CW operation. At present, more than 12 W have been obtained in CW operation in the TE/sub 2,3/ mode at 233 GHz.