Theory, Design, and Operation of Large-Orbit High-Harmonic Gyroklystron Amplifiers

Chu, K. R.; Furuno, D. S.; Luhmann, Neville C.; McDermott, D.B.; Vitello, P.; Ko, K.

doi:10.1109/tps.1985.4316457

Cited by 19 publications

(10 citation statements)

References 20 publications

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“…In particular, due to the use of the closed cavity, competition of modes with one and two longitudinal field oscillations was observed. In the experiment described in [18], two-and four-cavity multiplier versions of the LOG were implemented, in which the interaction in the input cavity took place at the fundamental harmonic, and in the output cavity, at the 5th cyclotron harmonic.…”

Section: Small-and Large-orbit Gyrotronsmentioning

confidence: 99%

Large-orbit Subterahertz and Terahertz gyrotrons

Bratman

Kalynov

Мануилов

2009

Radiophys Quantum El

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We review briefly the main ideas and achievements in the field of physics related to shortwavelength large-orbit gyrotrons, in which the coupling of electrons with the working mode and the discrimination of parasitic modes in the case of resonance at the high cyclotron harmonic are more efficient compared with conventional gyrotrons. The results of studying a new large-orbit gyrotron with moderate electron energies of 50-80 keV and comparatively low magnetic fields of 10.5-14 T are presented. In this gyrotron, high-power single-mode generation was obtained at the second and third cyclotron harmonics in the frequency range 0.55-1.00 THz. The prospects of development and application of short-wavelength large-orbit gyrotrons are discussed. SMALL-AND LARGE-ORBIT GYROTRONSThe conventional gyrotron with many off-axis elec-B B a) b) Fig. 1. Projections of electron trajectories onto the cross section of the cavity in a conventional gyrotron at the fundamental cyclotron resonance (a) and in a LOG at the high cyclotron harmonic (b).tron beamlets [1] and the gyrotron with an axis-encircling electron beam [2] were proposed and demonstrated in 1965 and 1968, respectively. A type of the oscillator with an axis-encircling beam, in which electrons move along helical trajectories around the axis of an axisymmetric electrodynamic system, is called a large-orbit gyrotron (LOG). This name is related to the fact that the LOG is usually operated at the high cyclotron harmonic and, therefore, the magnetic field in it, for the same operating frequency, is lower and the Larmor radius of electrons is greater compared with the conventional "small-orbit" gyrotron which is operated at the fundamental cyclotron resonance or the second cyclotron harmonic (Fig. 1). In the case where the conventional gyrotron and the LOG are operated at the same resonant harmonic, the electron "orbit" in them is the same and is determined by the Larmor radius of the electron in the same magnetic field.It should be emphasized that the conventional gyrotrons are perfect oscillators which provide, in particular, a radiation power of 1 MW in the quasi-continuous-wave regime at a high frequency of 0.17 THz with an efficiency of 50% (see, e.g., [3,4]). Conventional gyrotrons also work in the submillimeter-wave range [5][6][7][8] and recently have been used to overcome a 1-THz frequency when operated at the fundamental cyclotron resonance [9] and the second cyclotron harmonic [10]. At the same time, despite their relatively long history, LOGs have been realized in a comparatively small number of experiments and are still at the stage of fundamental research. Nevertheless, LOGs are still fairly attractive for operation at the high cyclotron harmonics since they ensure a more efficient coupling of electrons with the working-mode field and,

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Section: Small-and Large-orbit Gyrotronsmentioning

confidence: 99%

Large-orbit Subterahertz and Terahertz gyrotrons

Bratman

Kalynov

Мануилов

2009

Radiophys Quantum El

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“…That this equivalent circuit applies to the gyroklystron can be seen by examining eqn. (15) of Chu et al (1985 b) where the ratio of the effective cavity voltage to the AC beam current is proportional to [1 -2jQ(w -wo)/woJ -'.…”

Section: Principles Of Operationmentioning

confidence: 99%

“…Varian has demonstrated 50kW at 38GHz in a two-cavity gyroklystron (Jory et al 1977) with 40dB, gain and has designed a 400kW CW 35 G Hz gyroklystron (Caplan et al 1986) for applications in a planetary probing radar. The University of Maryland is developing a 30 MW, 10GHz four-cavity gyroklystron (Chu et al 1985 b) for application in large linear accelerators. The UCLA X-band gyroklystron (Furuno et al 1984, Chu et al 1985 achieved several hundred watts at a gain of 30 dB; this last experiment differed from the others in its beam formation method (RF acceleration) and interaction mechanism (high cyclotron harmonic, and hence low magnetic, field).…”

Section: Introductionmentioning

confidence: 99%

“…The University of Maryland is developing a 30 MW, 10GHz four-cavity gyroklystron (Chu et al 1985 b) for application in large linear accelerators. The UCLA X-band gyroklystron (Furuno et al 1984, Chu et al 1985 achieved several hundred watts at a gain of 30 dB; this last experiment differed from the others in its beam formation method (RF acceleration) and interaction mechanism (high cyclotron harmonic, and hence low magnetic, field). Gyroklystron amplifier experiments have so far reported efficiencies from a few percent to 30%.…”

Section: Introductionmentioning

confidence: 99%

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Penultimate cavity tuning of the gyroklystron amplifier†

Chu

Latham

Granatstein

1988

International Journal of Electronics

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“…Along with the already realized unique sources such as conventional gyrotrons with very strong magnetic fields [1][2][3][4][5] and free-electron lasers [6,7], the so-called large-orbit gyrotrons (LOGs) [8][9][10][11][12][13][14][15], which previously operated in centimeter-and millimeter-wave ranges, seem to be more promising and, possibly, simpler for the case of submillimeter waves. As opposed to a conventional gyrotron in which electrons move along the helical trajectories whose axes are uniformly distributed over the circumference (or in a thin ring) with radius significantly exceeding the Larmor radius of particles, all particles in the LOGs perform the Larmor rotation round the cavity axis as they move along this axis.…”

Section: Introductionmentioning

confidence: 99%

Submillimeter-wave large-orbit gyrotron

Bratman

Kalynov

Мануилов

et al. 2005

Radiophys Quantum Electron

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We develop a thermionic-emission electron-optical system forming a dense beam of electrons moving along helical trajectories round the axis of a gyrotron cavity. The maximum beam current is 4 A and the pitch-factor of electrons is 1.0 for a particle energy of 250 keV and a pulse duration of 10 µs. Using such a beam in a gyrotron operated at the third cyclotron harmonic, we obtain single-mode oscillation with a power of 10 µs in the T E 3,8 and T E 3,9 modes with frequencies 371 and 414 GHz, respectively.

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Theory, Design, and Operation of Large-Orbit High-Harmonic Gyroklystron Amplifiers

Cited by 19 publications

References 20 publications

Large-orbit Subterahertz and Terahertz gyrotrons

Large-orbit Subterahertz and Terahertz gyrotrons

Penultimate cavity tuning of the gyroklystron amplifier†

Submillimeter-wave large-orbit gyrotron

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