Rapid frequency step-switching in submillimeter wave gyrotrons (Gyrotrons FU III and FU IV)

Idehara, T.; Shimizu, Yuko; Ogawa, I.; Tatsukawa, Toshiaki; Brand, G. F.

doi:10.1063/1.873533

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…Frequency and power modulation are useful for extending a gyrotron's applications to fields like communication and scientific measurements. Rapid frequency modulation by changing the cathode voltage was described theoretically and verified experimentally in [35]. The principle is that by varying the cathode voltage V c (accelerating voltage), the beam velocity is changed, which results in a change of the electron mass and then in the modulation of cyclotron frequency.…”

Section: Cathode Voltage -The Frequency Tuning Methodsmentioning

confidence: 95%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Nowak

2022

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This paper outlines the principle of the DNP-NMR technique. The gyrotron, as a very promising microwave source for NMR spectroscopy, is evaluated. Four factors: power stability, power tuning, frequency stability, and frequency tuning determine the usability of the gyrotron device. The causes of instabilities, as well as the methods of overcoming limitations and extending usability are explained with reference to the theory, the numerical and experimental results reported by gyrotron groups.

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Section: Cathode Voltage -The Frequency Tuning Methodsmentioning

confidence: 95%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Nowak

2022

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“…Experimental results for frequency switching between two fundamental modes and between a fundamental and a second harmonic mode have been demonstrated in several experiments (see, e.g. [24,25]). The main advantageous characteristic of this method is that it allows rapid (in few microseconds) frequency switching because the accelerating potential applied to the gun can be changed very quickly and easily with a great precision.…”

Section: Frequency Control In Gyrotrons -Possibilities and Limitationsmentioning

confidence: 94%

Resonant Cavities for Frequency Tunable Gyrotrons

Sabchevski

Idehara

2007

Int J Infrared Milli Waves

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In this paper we present, discuss and compare several concepts based on both well-known and novel ideas for tunable gyrotron cavities. Although theoretical and design considerations are presented and discussed together the main focus is on the underlying principles and feasibility of different approaches rather than on their specific implementations. Illustrative examples are provided for configurations and frequency range appropriate for gyrotrons used as radiation sources for NMR spectroscopy with signal enhancement through DNP.

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“…The third possibility (which is rarely used due to the additional technical complications that it introduces) involves changing the dimensions and the shape of the cavity mechanically or by temperature control of the expansion/contraction of the resonator [52]. Efficient multi-frequency gyrotrons that are step-tunable in wide frequency ranges have been demonstrated in numerous experiments [50,[53][54][55][56][57][58][59][60]. An already classical but still impressive example of a stepwise tunability in a wide frequency band is the GYROTRON V developed at the University of Sydney [53].…”

Section: Characteristic Features Of the Gyrotrons And Their Radiationmentioning

confidence: 99%

The Gyrotrons as Promising Radiation Sources for THz Sensing and Imaging

et al. 2020

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The gyrotrons are powerful sources of coherent radiation that can operate in both pulsed and CW (continuous wave) regimes. Their recent advancement toward higher frequencies reached the terahertz (THz) region and opened the road to many new applications in the broad fields of high-power terahertz science and technologies. Among them are advanced spectroscopic techniques, most notably NMR-DNP (nuclear magnetic resonance with signal enhancement through dynamic nuclear polarization, ESR (electron spin resonance) spectroscopy, precise spectroscopy for measuring the HFS (hyperfine splitting) of positronium, etc. Other prominent applications include materials processing (e.g., thermal treatment as well as the sintering of advanced ceramics), remote detection of concealed radioactive materials, radars, and biological and medical research, just to name a few. Among prospective and emerging applications that utilize the gyrotrons as radiation sources are imaging and sensing for inspection and control in various technological processes (for example, food production, security, etc). In this paper, we overview the current status of the research in this field and show that the gyrotrons are promising radiation sources for THz sensing and imaging based on both the existent and anticipated novel techniques and methods.

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Rapid frequency step-switching in submillimeter wave gyrotrons (Gyrotrons FU III and FU IV)

Cited by 7 publications

References 9 publications

Bulletin of the Polish Academy of Sciences: Technical Sciences

Bulletin of the Polish Academy of Sciences: Technical Sciences

Resonant Cavities for Frequency Tunable Gyrotrons

The Gyrotrons as Promising Radiation Sources for THz Sensing and Imaging

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