Frequency Tunable Gyrotron FU CW VA for Measuring Hyperfine Split of Positronium

Dumbrājs, O.; Idehara, T.

doi:10.1007/s10762-010-9709-x

Cited by 11 publications

(3 citation statements)

References 7 publications

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“…Compared with the previous (cylindrical resonator, its diffractive Q factor is higher and the starting currents for excitation of the operating modes TE 0,3,l are lowerfor large axial indices l. As a result, the simulations indicate that the optimized design of the cavity extends the tunability band to 3 GHz [37]. More details about the experimental set-up in which this radiation source is embedded are given in the next section (see Sec.…”

Section: Gyrotron Fu Cw Vmentioning

confidence: 90%

“…An optimized modification of this gyrotron, called FU CW IX has an up-tapered cavity [37]. Compared with the previous (cylindrical resonator, its diffractive Q factor is higher and the starting currents for excitation of the operating modes TE 0,3,l are lowerfor large axial indices l. As a result, the simulations indicate that the optimized design of the cavity extends the tunability band to 3 GHz [37].…”

Section: Gyrotron Fu Cw Vmentioning

confidence: 97%

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

Idehara

Sabchevski

2012

J Infrared Milli Terahz Waves

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Powerful sources of coherent radiation in the sub-terahertz and in the terahertz frequency range of the electromagnetic spectrum are necessary for a great and continuously expanding number of applications in the physical research and in various advanced technological processes as well as in radars, communication systems, for remote sensing and inspection etc.. In recent years, a spectacular progress in the development of various gyrodevices and in particular of the powerful high frequency (sub-terahertz and terahertz) gyrotron oscillators has demonstrated a remarkable potential for bridging the so-called terahertz power gap and stimulated many novel and prospective applications. In this review paper we outline two series of such devices, namely the Gyrotron FU Series which includes pulsed gyrotrons and Gyrotron FU CW Series which consist of tubes operated in a CW (continuous wave) or long pulse mode, both developed at the FIR FU Center. We present the most remarkable achievements of these devices and illustrate their applications by some characteristic examples. An outlook for the further extension of the Gyrotron FU CW Series is also provided.

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Section: Gyrotron Fu Cw Vmentioning

confidence: 90%

Section: Gyrotron Fu Cw Vmentioning

confidence: 97%

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

Idehara

Sabchevski

2012

J Infrared Milli Terahz Waves

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“…It is known [9] that gyrotrons are prom ising sources of intense terahertz radiation. They may be used efficiently in such terahertz radiation applica tions as the dynamic polarization of nuclei in nuclear magnetic resonance spectroscopy [10], the study of the fine structure of positronium [11], remote sensing of concealed radioactive materials [12], the produc tion of plasma [13], etc. However, the efficiency of ter ahertz gyrotron operation is still relatively low.…”

Section: Introductionmentioning

confidence: 99%

On the theory of longitudinally inhomogeneous waveguides with impedance walls

Maksimenko

Zaginaylov

Shcherbinin

2015

Phys. Part. Nuclei Lett.

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The Maxwell equations for longitudinally inhomogeneous (irregular) waveguides with impedance walls are reduced equivalently to a system of ordinary differential equations by applying transverse expan sions. The obtained system of equations for amplitudes of the coupled modes is used to analyze gyrotron cav ities. Specifically, the effect of mode conversion and ohmic losses on the eigenfrequencies, quality factors, and field distributions in the gyrotron cavities operating in the submillimeter range is investigated.

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

Thumm

2020

J Infrared Milli Terahz Waves

297

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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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Frequency Tunable Gyrotron FU CW VA for Measuring Hyperfine Split of Positronium

Abstract: New uptapered cavity is designed for the gyrotron FU CW VA enhancing its tunability and enabling its use for measurements of the hyperfine split of positronium.

Cited by 11 publications

References 7 publications

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

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

On the theory of longitudinally inhomogeneous waveguides with impedance walls

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

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