94 GHz heavily loaded TE/sub 01/ gyro-TWT

Summary form only given, as follows. A high power TE/sub 01/ gyro-TWT is being constructed at UCD that is driven by a 100 kV, 5 A, MIG electron beam with alpha=vt/vz=1.0 and 5% axial velocity spread. The interaction circuit is heavily loaded for stability and is predicted by our large-signal simulation code to generate 140 kW at 94 GHz with 28% efficiency, 50 dB saturated gain and 5% bandwidth. Linear theory has been used to determine the threshold start-oscillation beam current for absolute instability and the critical section lengths for the potential harmonic gyro-BWO interactions. The MIG was designed with FINELGUN and has been fabricated. The edges of the emitter are coated with molybdenum to suppress edge emission. The input and output couplers transmit the TE/sub 01/ mode through the intermediary of a TE/sub 51/ coaxial mode and have been tested. The interaction circuit with a cutoff of 91 GHz has been coated with graphite and displays a loss of 70 dB at 97 GHz.