Gyrotrons belong to the family of high-power coherent radiation sources known as Electron Cyclotron Masers (ECMs) and are based on the physical mechanism of the ECM-instability, converting electron rotational kinetic energy into coherent electromagnetic radiation. The worldwide gyrotron R&D is mainly driven by the application in heating a magnetically confined fusion plasma, which requires coherent radiation sources with MW power-level in the sub-THz frequency range. In the last two decades, an application for gyrotrons emerged in the field of Nuclear Magnetic Resonance (NMR) spectroscopy, where a dramatic enhancement in sensitivity can be achieved via Dynamic Nuclear Polarization (DNP), requiring a low-power (~1-10W), sub-THz frequency (
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