Development program for a 200 kW, CW, 28-GHz gyroklystron. Quarterly report No. 8, January--March 1978

The objective of this program is to develop a microwave amplifier or oscillator capable of producing 200 kW CW power output at 28 GHz. The use of the gyrotron or cyclotron resonance interaction is being pursued. During this quarter the first CW oscillator design was pulsed tested up to 167 kW peak and 20 kW average output. CW testing of the tube was satisfactory provided parameters were set for zero microwave output, but operation with CW output was plagued with gassing and arcing internal to the tube. A second tube was constructed with minor design changes to eliminate the gassing problems. Preliminary testing of this tube indicates improvement. Possible design changes for future tubes are discussed including output coupling alternatives and output window changes.