Study of high-power Ka-band second-harmonic gyroklystron amplifier

Zasypkin, E. V.; Moiseev, M. A.; Gachev, I. G.; Antakov, I. I.

doi:10.1109/27.532949

Cited by 43 publications

(15 citation statements)

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“…Fundamental and second harmonic two cavity gyroklystron amplifiers at 9.87 and 19.7 GHz, designed as drivers for linear colliders, achieved peak output powers of 20 and 30 MW, respectively, with efficiencies near 30% [5,6]. A two cavity Ka-band gyroklystron, developed for radar applications, produced 750 kW at 35 GHz in the TE 021 mode at 24% efficiency [8]. In W -band, a pulsed four cavity gyroklystron amplifier achieved 65 kW peak output power at 26% efficiency with 300 MHz bandwidth [9].…”

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Experimental Demonstration of aW-Band Gyroklystron Amplifier

et al. 1997

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The experimental demonstration of a four cavity W -band (93 GHz) gyroklystron amplifier is reported. The gyroklystron has produced 67 kW peak output power and 28% efficiency in the TE 011 mode using a 55 kV, 4.3 A electron beam. The full width at half maximum instantaneous bandwidth is greater than 460 MHz, a significant increase over the bandwidth demonstrated in previous W -band gyroklystron amplifier experiments. The amplifier is unconditionally stable at this operating point. Experimental results are in good agreement with theoretical predictions. [S0031-9007 (97)04699-1] PACS numbers: 84.40.FeThe continuing need for high power sources of microwave and millimeter wave radiation for such varied applications as high resolution radars, linear accelerators [1], magnetic resonance imaging [2], and communications has led to extensive research on gyroklystron amplifiers [3][4][5][6][7][8][9][10]. Much like a conventional klystron, the gyroklystron consists of several resonant cavities separated by drift sections cut off to the operating mode. As evidenced in numerous experiments, the interaction of the beam with the trapped mode in the cavity, based on the electron cyclotron maser instability, can reliably and efficiently generate high power, moderate bandwidth electromagnetic radiation at microwave and millimeter wave frequencies. For example, a three cavity C-band gyroklystron amplifier produced 54 kW peak output power and 30% efficiency in the TE 101 at 4.5 GHz [3]. The saturated gain was 30 dB and the FWHM bandwidth was 0.4%. A three cavity X-band gyroklystron achieved 16 kW peak output power and 45% efficiency with a FWHM bandwidth of 1% [4]. Fundamental and second harmonic two cavity gyroklystron amplifiers at 9.87 and 19.7 GHz, designed as drivers for linear colliders, achieved peak output powers of 20 and 30 MW, respectively, with efficiencies near 30% [5,6]. A two cavity Ka-band gyroklystron, developed for radar applications, produced 750 kW at 35 GHz in the TE 021 mode at 24% efficiency [8]. In W -band, a pulsed four cavity gyroklystron amplifier achieved 65 kW peak output power at 26% efficiency with 300 MHz bandwidth [9]. A continuous wave version of the device demonstrated 2.5 kW average output power.The gyroklystron interaction, which takes place in standing wave cavities, inherently gives high efficiency, gain, and output power, but lower bandwidth than devices which rely on traveling wave interactions, such as the gyro-traveling-wave tube (gyro-TWT). Obtaining wider bandwidth without the concomitant problems of the absolute instability associated with the gyro-TWT interaction is an important area of study. It is the goal of the present work to demonstrate a high power, high gain, efficient, stable W -band gyroklystron amplifier with greater bandwidth than previously achieved, and to elucidate the basic physics of gyroamplifiers by comparing theoretical predictions with experimental results.This paper presents an experimental study of a four cavity W-band gyroklystron amplifier operating in the TE 011...

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Experimental Demonstration of aW-Band Gyroklystron Amplifier

et al. 1997

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“…In this case, the total length of the electrodynamic system, which is determined by the length of the uniform section in the magnetic field of the permanent magnet, remains constant. The eigenfrequency of the central cavity f Under these conditions, the regime of maximum amplification is realized in a three-cavity gyroklystron [7]. The Q-factor of the central cavity is Q cen = 450, and the Q-factors of the other two cavities are the same as in a two-cavity amplifier, i.e., Q in = 600 and Q out = 1050.…”

Section: Three-cavity Gyroklystron With Synchronous Cavitiesmentioning

confidence: 98%

“…The calculated values of the pitch factor of the beam and relative spread of rotational velocities of the electrons are g 0 = 1.1 and δβ ⊥ = 23%, respectively, for an accelerating voltage of 70 kV and a current of 20 A. As with the gyroklystron described in [7], the electron gun is coupled with the system of diffraction excitation of the input cavity. The TE 01 mode of the feeding waveguide, which passes through an opening in the cathode, is converted by a mirror transformer to the TE 02 mode that propagates in the input waveguide and excites the working TE 021 mode in the first cavity through the coupling diaphragm.…”

Section: Electron-optical and Electrodynamic Systems Of The Gyroklystronmentioning

confidence: 99%

“…In the early 1990s, IAP RAS developed and studied a gyroklystron at the second gyrofrequency harmonic. It operated at a frequency of 35 GHz in a magnetic field of 0.7 T, which was produced by a cryomagnet [7]. In the process of experimental studies of this amplifier, a pulsed power of 260 kW was achieved with an efficiency of 18%, an amplification coefficient of 17 dB, and a bandwidth of the amplified frequencies of 0.1%.…”

Section: Introductionmentioning

confidence: 99%

“…Basing on the data from [7], we designed a gyroklystron operating in the field of a permanent magnet. The results of studying it experimentally are presented in this paper.…”

Section: Introductionmentioning

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Experimental studies of a gyroklystron operating in the field of a permanent magnet

Antakov

Gachev

Zasypkin

2011

Radiophys Quantum El

Self Cite

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621.385.69We have developed and tested a gyroklystron operating with the second harmonic of the electron cyclotron frequency at a frequency of 32.3 GHz in the field of a permanent magnet. In the twoand three-cavity versions of the gyroklystron, the peak power of the output radiation reached 320 kW with an efficiency of 30%, an amplification coefficient of 20-25 dB, and an operating frequency bandwidth of 0.05%. In the wide-band version of the gyroklystron, the amplification bandwidth was equal to 0.27% for an output power of 200 kW and an amplification coefficient of 13 dB.

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State-of-the-Art of High-Power Gyro-Devices and Free Electron Masers

Thumm

2020

J Infrared Milli Terahz Waves

290

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STATE-OF-THE-ART OF HIGH POWER GYRO-DEVICES AND FREE ELECTRON MASERSAt present, gyrotron oscillators are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH) and diagnostics of magnetically confmed plasmas for generation of energy by controlled thermonuclear fusion. 140 GHz gyrotrons with output power Pout = 0.58 MW, pulse length 't = 2.0 s and efficiency 11 = 34 % are commercially available. Diagnostic gyrotrons deliver P out = 40 kW with 't = 40 J-lS at frequencies up to 650 GHz (11 2_ 4 %). Recently, gyrotron oscillators have also been successfully used in matedal processing and plasma chemistry. Such technological applications require gyrotrons with the following parameters: f 2. 28 GHz , Pout = 10-30 kW, CW, 11 2. 30 %. This paper reports on achievements and problems related to the development of very high power mm-wave gyrotrons for long pulse or CW operation and describes the microwave technological pecularities of the different development steps. In addition, this work gives a short overview of the present development of gyrotrons for technological applications, quasi-optical gyrotrons, cyclotron autoresonance masers (CARMs), gyro-ldystrons, gyro-TWT amplifiers, gyro-BWO's and free electron masers (FEMs). The most impressive FEM output parameters are: Pout = 2GW, 't = 20 ns, 11 = 13 % at 140 GHz (LLNL) and Pout = 15 kW, 't = 20 J-tS, 11 = 5 % in the range from 120 to 900 GHz (UCSB). ENTWICKLUNGSSTAND VON HOCHLEISTUNGS-GYRO-RÖHREN UND FREI-ELEKTRONEN-MASERN Übersiebt Gyrotronoszillatoren werden derzeit vorwiegend als Hochleistungsmillimeterwellenquellen für die Elektron-Zyklotron-Resonanzheizung (ECRH) und Diagnostik von magnetisch eingeschlossenen Plasmen zur Erforschung der Energiegewinnung durch kontrollierte Kernfusion eingesetzt. 140 GHz Gyrotrons mit einer Ausgangsleistung von Pout = 0.58 MW bei Pulslängen von 't = 2.0 s und Wirkungsgraden von • 11 = 34% sind kommerziell erhältlich. Gyrotrons zur Plasmadiagnostik erreichen Frequenzen bis zu 650 GHz bei P out = 40 kW und 't = 40 ~-ts (11 2. 4 %). In jüngster Zeit jedoch finden Gyrotronoszillatoren auch für technologische Prozesse und in der Plasmachemie erfolgreich Verwendung. Dabei werden Röhren mit folgenden Parametern eingesetzt: f 2_ 28 GHz, Pout = 10-30 kW, CW, 11 2. 30 %. In diesem Beitrag wird auf den aktuellen Stand und die Probleme bei der Entwicklung von Hochleistungs-mm-Wellen-Gyrotrons für Langpuls-und Dauerstrichbetrieb sowie auf die mikrowellentechnischen Besonderheiten der einzelnen Entwicklungsphasen eingegangen: Außerdem wird auch kurz über den neuesten Stand der Entwicklung von Gyrotrons für technologische Anwendungen, quasi-optischen Gyrotrons, Zyklotron-Autoresonanz-Masern (CARMs), Gyroklystrons, Gyro-TWT-Verstärkern, Gyro-Rückwärtswellenoszillatoren (BWOs) und Frei-Elektronen-Maser (FEM) berichtet. FEM-Rekordausgangsparameter sind hier: Pout = 2 GW, 't = 20 ns, 11 = 13 % bei 140 GHz (LLNL) und Pout = 15 kW, 't = 20 J-lS, 11 = 5 % im Bereich von 120 bis 900 GHz (UCSB). Contents

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Study of high-power Ka-band second-harmonic gyroklystron amplifier

Cited by 43 publications

References 5 publications

Experimental Demonstration of aW-Band Gyroklystron Amplifier

Experimental Demonstration of aW-Band Gyroklystron Amplifier

Experimental studies of a gyroklystron operating in the field of a permanent magnet

State-of-the-Art of High-Power Gyro-Devices and Free Electron Masers

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