Высокоэффективный гиротрон с многоступенчатой рекуперацией остаточной энергии электронов

The results of combined simulation of physical processes in a medium power gyrotron of 4-mm wavelength range are presented. The methods of improving the quality of helical electron beam and the electron efficiency of the gyrotron, based on the optimization of electric field distribution in the near-cathode region, are realized. The design of the collector with 4-stage recovery of residual beam energy, based on the method of spatial separation of electrons in crossed azimuthal magnetic and axial electric fields, was developed. The value of total efficiency of the gyrotron equal to 71.8 % was achieved by improving the quality of the electron beam and by efficient energy recovery in the collector region.

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New possibilities of collectors with azimuthal magnetic field for multistage energy recovery in gyrotrons

Journal of Physics Conference Series ◽

10.1088/1742-6596/2103/1/012058 ◽

2021 ◽

Vol 2103 (1) ◽

pp. 012058

Author(s):

I Louksha ◽

P A Trofimov ◽

B D Usherenko

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Energy Recovery ◽

Trajectory Analysis ◽

Spatial Separation ◽

Total Efficiency ◽

Optimal Parameters ◽

Azimuthal Magnetic Field ◽

Electron Trajectories ◽

Collector Region

Abstract The results of modeling a collector with 4-stage recovery of residual electron energy for the SPbPU gyrotron with a frequency of 74.2 GHz and an output power of 100 kW are presented. For spatial separation of electrons with different energies, an azimuthal magnetic field created by a toroidal solenoid is used. An increase of the recovery efficiency and a decrease of the current of electrons reflected from the collector is achieved by reducing the spread of the radial position of the leading centers of electron trajectories at optimal parameters of the toroidal solenoid, as well as by using a sectioned electron beam. The trajectory analysis of the spent electron beam in the collector region showed the possibility of achieving the total efficiency of the gyrotron, close to 80%.

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Development of multistage energy recovery system for gyrotrons

ITM Web of Conferences ◽

10.1051/itmconf/20193002002 ◽

2019 ◽

Vol 30 ◽

pp. 02002

Author(s):

Pavel Trofimov ◽

Oleg Louksha

Keyword(s):

Magnetic Fields ◽

Electron Energy ◽

Energy Recovery ◽

Trajectory Analysis ◽

Spatial Separation ◽

Total Efficiency ◽

Helical Electron Beam ◽

Electric And Magnetic Fields ◽

Recovery System ◽

Collector Region

A four-stage depressed collector based on spatial separation of electrons with different energies in the crossed electric and magnetic fields was developed for the experimental SPbPU gyrotron. Modeling of the system of electron energy recovery and analysis of the distributions of electric and magnetic fields in the gyrotron collector region were performed. As a result of the theoretical estimations and the trajectory analysis of the helical electron beam, it is shown that the developed system provides recovery of the residual electron energy necessary to achieve the total efficiency of the gyrotron exceeding 70 %.

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Траекторный анализ в коллекторе с многоступенчатой рекуперацией энергии для прототипа гиротрона DEMO. Часть I. Идеализированное распределение магнитного поля

Журнал технической физики ◽

10.21883/jtf.2021.01.50284.123-20 ◽

2021 ◽

Vol 91 (1) ◽

pp. 135

Author(s):

О.И. Лукша ◽

П.А. Трофимов ◽

В.Н. Мануилов ◽

М.Ю. Глявин

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Electric Fields ◽

Beam Energy ◽

Trajectory Analysis ◽

Spatial Separation ◽

Maximum Efficiency ◽

Azimuthal Magnetic Field

The results of modeling of collector for the gyrotron prototype being developed for the DEMO project are presented. A trajectory analysis in a collector with a 4-stage recovery of the residual beam energy based on the method of spatial separation of electrons in crossed azimuthal magnetic and axial electric fields was performed. In this part of the study, the formation of the azimuthal magnetic field was carried out using a conductor located on the axis of the device. The study was performed for a spent electron beam with a velocity and coordinate distribution of particles close to those obtained in experiments with powerful gyrotrons. Due to a thorough choice of the geometry of the collector sections, a total gyrotron efficiency of more than 80% was achieved, which is close to maximum efficiency with perfect separation of fractions of an electron beam with different energies. The data obtained will be used for development of a toroidal solenoid designed to create an azimuthal magnetic field.

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Simulation of high-efficiency gyrotron with the system of multistage energy recovery

ITM Web of Conferences ◽

10.1051/itmconf/20193002001 ◽

2019 ◽

Vol 30 ◽

pp. 02001 ◽

Cited By ~ 1

Author(s):

Pavel Trofimov ◽

Oleg Louksha

Keyword(s):

Electron Beam ◽

Energy Recovery ◽

High Efficiency ◽

Beam Quality ◽

Particle Interaction ◽

Velocity Spread ◽

Total Efficiency ◽

Frequency Wave ◽

Electron Efficiency ◽

Collector Region

The results of simulations of helical electron beam formation and collecting, as well as high frequency wave-particle interaction processes, in the moderate-power experimental gyrotron with the frequency of 74.2 GHz are presented. Various methods of beam quality and electron efficiency improvement via optimization of electric and magnetic field distributions in the cathode region were realized. In the optimal operating regime with high pitch ratio and low velocity spread, the electron efficiency of about 46 % was calculated for the gyrotron with the magnetron injection gun including a control electrode and a cathode with sectioned emission. In the gyrotron collector region, a system of 4-stage electron energy recovery was used for enhancement of total efficiency of the device. By improving the quality of the electron beam and efficient energy recovery in the collector region, the total efficiency of the gyrotron equal to 71.8% was achieved.

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Lithography below 100 nm

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074367 ◽

1983 ◽

Vol 41 ◽

pp. 96-99

Author(s):

L. D. Jackel

Keyword(s):

Spatial Distribution ◽

Electron Beam ◽

Electron Scattering ◽

Electron Beam Lithography ◽

Substrate Material ◽

Local Electron ◽

Electron Dose ◽

Positive Resist ◽

Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

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Methods to Monitor and Improve the Performance of Specimen Holders for Transmission Electron Cryomicroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164738 ◽

1996 ◽

Vol 54 ◽

pp. 454-455

Author(s):

B. L. Armbruster ◽

B. Kraus ◽

M. Pan

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Electron Beam Irradiation ◽

Beam Irradiation ◽

Quality Of Data ◽

Electron Cryomicroscopy ◽

Thermal Equilibration ◽

Transmission Electron ◽

Electron Microscopes

One goal in electron microscopy of biological specimens is to improve the quality of data to equal the resolution capabilities of modem transmission electron microscopes. Radiation damage and beam- induced movement caused by charging of the sample, low image contrast at high resolution, and sensitivity to external vibration and drift in side entry specimen holders limit the effective resolution one can achieve. Several methods have been developed to address these limitations: cryomethods are widely employed to preserve and stabilize specimens against some of the adverse effects of the vacuum and electron beam irradiation, spot-scan imaging reduces charging and associated beam-induced movement, and energy-filtered imaging removes the “fog” caused by inelastic scattering of electrons which is particularly pronounced in thick specimens.Although most cryoholders can easily achieve a 3.4Å resolution specification, information perpendicular to the goniometer axis may be degraded due to vibration. Absolute drift after mechanical and thermal equilibration as well as drift after movement of a holder may cause loss of resolution in any direction.

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Double layers in the downward current region of the aurora

Nonlinear Processes in Geophysics ◽

10.5194/npg-10-45-2003 ◽

2003 ◽

Vol 10 (1/2) ◽

pp. 45-52 ◽

Cited By ~ 32

Author(s):

R. E. Ergun ◽

L. Andersson ◽

C. W. Carlson ◽

D. L. Newman ◽

M. V. Goldman

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Phase Space ◽

Electric Field ◽

Electric Fields ◽

Double Layers ◽

Parallel Electric Field ◽

Electrostatic Waves ◽

Current Region ◽

Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

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