DEVELOPMENT AND TEST OF A 500-KW, 8-GHZ GYROTRON

Varian Associates Inc. has developed an 8-GHz gyrotron that generates 500 kW and is capable of depressed collector operation. The output is extracted transversely from the circuit into two WR137 rectangular wav eguides using modified pillbox windows. The device will be used for lo wer hybrid heating of the FTU tokamak in Frascati, Italy, and has cons equently been designed to produce over 400 kW when operated into a 4:1 VSWR. The current tube produces 1-s pulses every 10 min with the outp ut power adjustable from approximately 150 to over 500 kW by changing only beam and mod anode voltage. The sensitivity to operating paramete rs is extremely low making the tube easy to operate and unusually tole rant of variations in voltages and currents.