Experimental demonstration of a W-band gyro-BWO using a helically corrugated waveguide

The experimental demonstration of a gyrotron backward wave oscillator (gyro-BWO) using a cusp electron gun and helically corrugated waveguide will be presented. Operating in the W-band frequency range the gyro-BWO is predicted to output ~10 kW with a frequency tuning range of 85-104 GHz at 18% electronic efficiency before the energy recovery. The annular axis-encircling electron beam has been experimentally measured to show a 1.5 A, 40 kV beam with velocity ratio up to 1.56 at 1.65 T. Preliminary microwave radiation has been measured over a frequency range of 92 to 100 GHz.