Design of a 460 GHz second harmonic gyrotron oscillator for use in dynamic nuclear polarization

We report the design of a gyrotron oscillator for continuous operation at 460 GHz at a power level of up to 50 W. The gyrotron oscillator will be used in dynamic nuclear polarization (DNP) NMR (nuclear magnetic resonance) studies with a 700 MHz (/sup 1/H), 16.5 T NMR spectrometer and will operate at the second harmonic of the electron cyclotron frequency.