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In this paper the result of experimental investigation of one of the key elements of a sub-millimeter wave (260 GHz) broadband gyro-TWT's radiation input/output system is presented. A quasi-optical waveguide device based on the Talbot's effect effectively separates power flows of input and output radiation in the required frequency range.
Research activity on development of gyrotron travelling-wave tubes (gyro-TWTs) at the Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS) is presented. In the gyro-TWTs under discussion a helically corrugated waveguide is used as a principal part of their microwave circuits which ensures a number of advantages over other configurations of the gyro-TWTs.
The ferroelectric cathode is a cold cathode based on surface plasma, that is not widely known to the gyrotron community. It was assembled and operated is several setups of gyrotrons. Radiation was obtained in the Ka band and the W band. Power in the range of 1–30 kW with interaction efficiency of 10–15% were measured. Experiential results and the potential exploitation of the cathode will be presented.
In this report we demonstrate a high-spectral-resolution terahertz (THz) imaging system on the basis of a THz quantum-cascade laser (QCL), a fast scanning mirror (FSM), and a cryogenic-cooled Ge:Ga detector. During the scan through an absorption cell filled with methanol (CH3OH), spectral information is obtained through QCL frequency tuning within a range that covers the feature of interest. Our results...
Broadband laser based terahertz systems for multilayer thickness inspections are getting established in industrial environments, such as in the quality control for paint processes in the automotive industry. Within this contribution we address another highly attractive and complementary industrial terahertz application by the thickness and density inspection of thick and multilayer plastics as for...
The concept of a CW THz range gyrotrons operated at the second cyclotron harmonic is presented. To suppress the mode competition effects a double beams scheme is applied. The helical electron beams are formed in a double-beam triode magnetron-injection gun (MIG), where both emitters of the electron beams are located on a common cathode of the conventional MIG. Results of numerical simulation of electron...
An ultra-wide band W-Band travelling wave tube using staggered double vane slow wave structure (SDV-SWS) combined with plan alignment three pencil beams is investigated in this paper. Instead of only using the fundamental mode, the first two modes of SDV-SWS are designed to match with the same electron beam to promote the bandwidth. Particle in cell (PIC) simulations with our new type of two stages...
Microfabricated vacuum-tube THz sources are of great interest for numerous applications such as communications, radar, sensors, imaging, etc. Recently, miniaturized sheet-beam traveling-wave tubes for THz and sub-THz operation have attracted a considerable interest. In this paper, we present the results of modeling and development of medium power (10–100 W) G-band traveling-wave tube amplifiers with...
We report on a novel waveguide concept which combines antiresonant and metamaterial guidance. The guidance is achieved in the hollow core and loss as low as 2.3 dB/km are theoretically achievable in the THz frequency range. Both purely antiresonant and antiresonant metamaterial fibers have been fabricated and characterized. The realized metamaterial fiber has been simulated to have 0.3 dB/m loss at...
In the frame of a collaborative effort between the European GYrotron Consortium (EGYC), the European domestic agency Fusion for Energy (F4E) and the Industrial partner Thales Electron Devices (TED), the first continuous wave (CW) prototype of the EU gyrotron for the ITER Electron Cyclotron Heating system has been manufactured by TED and delivered to the Karlsruhe Institute of Technology (KIT) by end...
In this paper, a node-free anisotropic hollow-core anti-resonant fiber has been proposed to give low transmission loss in the near-IR to mid-IR spectral regime. The proposed silica-based fiber design shows transmission loss below 10 dB/km at 2.94 μm with multiple low loss transmission bands. Transmission loss of 1 dB/m up to 4 μm is also predicted.
We present a simple cross-calibration procedure for measuring THz power with room-temperature pyroelectric detectors. When efficiently coupled, large-area, metal-film-coated lithium tantalate pyroelectric detectors are perfectly capable of detecting microwatt average power levels or less from THz sources, pulsed or cw. Here we focus on a brass flared-horn coupling technique that increases the pyroelectric...
Research activity on development of various types of gyro-devices at the Institute of Applied Physics of Russian Academy of Sciences (IAP RAS) and at industrial company GYCOM Ltd is presented. Recent results of the development are illustrated by a number of examples of fabricated and tested gyrotrons-oscillators and gyro-amplifiers operating at very different frequencies.
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