Efficiency enhancement of gyrotron based setups for materials processing

Second harmonic 24–28 GHz CW gyrotrons and series of gyrotron based setups for material processing and Electron Cyclotron Resonance Ion Sources (ECRIS) has been developed at IAP RAS. The possibility of significant output efficiency enhancement due to energy recovery for gyrotrons operating at cyclotron harmonic is demonstrated. The efficiency of 60% at 6 kW output power level at second harmonic 24 GHz gyrotron has been obtained by magnetic field profile optimization and single-stage energy recovery of the spent electron beam. It is shown, that the energy to sintering process can be significantly reduced (1.5–2 times) by simultaneous control of gyrotron voltage and solenoid current. Different varieties of broadband frequency gyro devices — multi-frequency or fast-swept in time operation — are under investigation for ECRIS. The double-frequency CW 10 kW second harmonic gyrotron with 2% fast frequency and a frequency-tunable gyro-BWO operating at center frequency of 60 GHz with CW output power about 10 kW are presented.