Development of gyrotron FU CW VII for 600 and 300 MHz DNP-NMR

Kosuga, K.; Idehara, T.; Ogawa, I.; Saito, T.; Agusu, La; Kanemaki, T.; Smith, Mark E.; Dupree, R.

doi:10.1109/icimw.2009.5324604

Cited by 3 publications

(4 citation statements)

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“…The black circle is a fundamental forward wave oscillation, the square is a second harmonic forward wave oscillation and the diamond is a fundamental backward wave (BW) oscillation. Traditionally, gyrotrons interact with the fundamental forward wave [13], [14], [20]; however, the second harmonic forward wave is useful for higher frequency experiments [15], [16], [58], [59] and the BW interaction is used at the first or second harmonic to provide the frequency tunability in gyrotrons for DNP NMR experiments.…”

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

“…Gyrotrons were developed at power levels of 10–100 W for application to DNP NMR and EPR experiments [13]–[16], [20], [58], [59]. The gyrotrons for DNP NMR must meet exacting specifications for reliability, efficient power conversion, frequency bandwidth and signal stability, as listed in Table I.…”

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

“…With the completion of two additional second harmonic sources in 2009 [58], [59], the first DNP enhancements using second harmonic gyrotrons were reported in 2010 at 260 GHz [17] and 395 GHz [19]. The 260 GHz experiment, shown in Fig.…”

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

“…Tuning of over 1 GHz has recently been achieved in a 395 GHz gyrotron [59], [85]. The 1.6 GHz of tuning, shown in Fig.…”

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

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THz Dynamic Nuclear Polarization NMR

Nanni

Barnes

Griffin

et al. 2011

IEEE Trans. Terahertz Sci. Technol.

167

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Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) spectroscopy by using high frequency microwaves to transfer the polarization of the electrons to the nuclear spins. The enhancement in NMR sensitivity can amount to a factor of well above 100, enabling faster data acquisition and greatly improved NMR measurements. With the increasing magnetic fields (up to 23 T) used in NMR research, the required frequency for DNP falls into the THz band (140–600 GHz). Gyrotrons have been developed to meet the demanding specifications for DNP NMR, including power levels of tens of watts; frequency stability of a few megahertz; and power stability of 1% over runs that last for several days to weeks. Continuous gyrotron frequency tuning of over 1 GHz has also been demonstrated. The complete DNP NMR system must include a low loss transmission line; an optimized antenna; and a holder for efficient coupling of the THz radiation to the sample. This paper describes the DNP NMR process and illustrates the THz systems needed for this demanding spectroscopic application. THz DNP NMR is a rapidly developing, exciting area of THz science and technology.

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Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

“…Tuning of over 1 GHz has recently been achieved in a 395 GHz gyrotron [59], [85]. The 1.6 GHz of tuning, shown in Fig.…”

Section: Gyrotrons For Dnp Nmrmentioning

confidence: 99%

See 2 more Smart Citations

THz Dynamic Nuclear Polarization NMR

Nanni

Barnes

Griffin

et al. 2011

IEEE Trans. Terahertz Sci. Technol.

167

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

Thumm

2020

J Infrared Milli Terahz Waves

308

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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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