A 1.2 THz third-harmonic gyrotron with novel azimuthally segmented electron beam

We present the development of a 1.2 THz third-harmonic continuous-wave gyrotron, designed to deliver tens of watts of output for dynamic nuclear polarization nuclear magnetic resonance spectroscopy. To address the exceptionally fierce mode competition issue, we propose the use of a novel azimuthally segmented electron beam to facilitate mode-selective enhancement in the coupling strength of the desired third-harmonic operating mode. Simulation results reveal that the implementation of the azimuthally segmented electron beam can help to selectively lower the starting current, broaden the effective operating regime of the third-harmonic mode, and significantly increase the output power.