Influence ofBeam Currenit andCooling 'Vater Temii,perature on theFrequeicyCharacteristics ofSub-Mi'llimieter WaveGyrotron FU-ILV

Thecharacteristics ofthef'requency drift areexaminedpr-cisely fortheSMMW gyrotron PU-T-1V. The drift ofcenterfrequency isreduced tobele1s than a fewMHzduring 20 minutes. Then, thefrequency. thecooling-water temperature, thebeamcurrent and theoutput power aremonitored simultaneously to-i exanmine therelationship amongthese parameters. The results inodicate thatthefrequency drift iscaused by thermal expansion andcontaction ofthecavity ina -w 10MHz rangeandisalsoaffe-ted byncnthermalfreuency pulling effect ofbeamcurrent when thebehaviors within afewMHzrange areconsidered.