Design of a Compact Sub-Terahertz Gyrotron for Spectroscopic Applications

Abstract

In this paper we present the initial design of a novel and versatile high frequency gyrotron with parameters suitable for application to various spectroscopic studies that require coherent radiation in the subterahertz frequency range (such as NMR/DNP spectroscopy, ESR spectroscopy, spectrometer based on the X-ray detected magnetic resonance etc.). The most characteristic feature of the design is that it utilises a compact, cryogen-free 8 T superconducting magnet. As a result, the overall dimensions of the entire device are considerably reduced in comparison with the previously developed tubes belonging to the Gyrotron FU and Gyrotron FU CW series. This makes the novel gyrotron highly portable to diverse laboratory environments and easily embeddable to different measuring systems. The electron-optical system (EOS) of the tube is based on a compact low-voltage magnetron injection gun (MIG), which has been specially designed and optimized together with the resonant cavity using our problem-oriented software package GYROSIM for CAD of gyrotrons. The tube operates at the second harmonic of the cyclotron frequency and generates a radiation with an output power of about 100 W and a frequency tunable up to around 424 GHz, respectively.

Design of an Optimized Resonant Cavity for a Compact Sub-Terahertz Gyrotron

“…As it has already been pointed out in [1], the closest potential competitor to the operating TE 8,2 mode is the TE 0,2 mode at the fundamental of the cyclotron frequency. The simulations however have shown that this mode is suppressed by the operating mode.…”

“…Its initial design that includes both the design of the electron-optical system (EOS) and the resonant cavity was presented in [1]. It is expected that the tube will operate at the second harmonic of the cyclotron frequency and will generate radiation in a CW regime with an output power of about 100 W and frequency tunable to up to 424 GHz, respectively.…”

Gyrotrons for High-Power Terahertz Science and Technology at FIR UF

“…From the other side, it is clear that when used as radiation sources in a sophisticated laboratory environment it is easier to embed them into the rest of the equipment if their dimensions are smaller. In recent years, the availability of compact cryo-free superconducting magnets has made it possible to develop much more compact gyrotrons [18][19][20]. According to the nomenclature adopted at FIR UF, these recently developed devices are marked by the letter "C", which stands for "compact".…”

Development and Applications of High—Frequency Gyrotrons in FIR FU Covering the sub-THz to THz Range

“…Bulky and heavy devices like conventional gyrotrons are not suitable for such systems. This motivated us to develop a concept of a compact gyrotron [41,42], which is based on the utilization of compact liquid He-free superconducting magnets and slim tubes with a special design allowing its insertion in the relatively small diameter bore of the solenoid. The mentioned special design envisages also development of an optimized low-voltage and low-current MIG with reduced (minimized) radial dimensions.…”