60 GHz gyrotron development program. Quarterly report No. 8, April-June 1981

The objective of this program is to develop a microwave oscillator designed to produce 200 kW of CW output power at 60 GHz. Neither tunability nor bandwidth is considered an important parameter in the design but efficiency is. Mode purity in the output waveguide is not a requirement for the device, but the circular electric mode is considered desirable because of its low loss properties. Initial tests of X-1 were completed. At a pulse duration of 265 ..mu..s a peak output power of 150 kW wass measured. A body heating phenomenon was identified as a drift tube oscillation. The second experimental tube incorporating a cathode in an optimized location and a water cooled anode is available for test after test set debugging. The third experimental tube incorporating a modified drift tube is under construction. A CW gyrotron is also under construction. Quotes for a spare superconducting solenoid magnet system have been received. Debugging of the test set, using X-1 as a load, is continuing. A variety of waveguide components have been completed. The gyrotron behavior investigation is continuing. The arcing and crowbar, new cathode material, parameter space, rf output stability, low level starting and efficiency investigations were completed during themore » quarter.« less