Траекторный анализ в коллекторе с многоступенчатой рекуперацией энергии для прототипа гиротрона DEMO. Часть II. Тороидальное магнитное поле

The results of modeling of a collector with four-stage recovery of the residual beam energy for the prototype gyrotron designed for the DEMO project are presented. For spatial separation of electrons with different energies, the azimuthal magnetic formed by a toroidal solenoid is used. An increase of the recovery efficiency and a decrease of the flow of electrons reflected from the collector are achieved by reducing the spread of radial position of the leading centers of electron trajectories at the optimal parameters of the toroidal solenoid, as well as by using a sectioned electron beam. Trajectory analysis of the spent beam with electron velocity and coordinate distributions close to those obtained in experiments with high-power gyrotrons showed the possibility of achieving an overall efficiency of the gyrotron higher than 80 %, which is close to the maximum efficiency at ideal separation of electron beam fractions with different energies.

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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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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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A Universal Equation for the Emission Range of X Rays from Bulk Specimens

Microscopy and Microanalysis ◽

10.1017/s143192760707081x ◽

2007 ◽

Vol 13 (5) ◽

pp. 354-357 ◽

Cited By ~ 7

Author(s):

Raynald Gauvin

Keyword(s):

Electron Beam ◽

Free Path ◽

Beam Energy ◽

Mean Free Path ◽

Electron Beam Energy ◽

X Rays ◽

Bulk Materials ◽

Universal Equation ◽

Electron Trajectories ◽

X Ray

The derivation of a universal equation to compute the range of emitted X rays is presented for homogeneous bulk materials. This equation is based on two fundamental assumptions: the φ(ρz) curve of X-ray generation is constant and the ratio of the emitted to the generated X-ray range is equal to the ratio of the emitted to the generated X-ray intensity. An excellent agreement is observed with data obtained from Monte Carlo simulations of 200,000 electron trajectories in C, Al, Cu, Ag, Au, and an Fe–B alloy with boron weight fractions equal to 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.99, performed with the electron beam energy varied from 1 to 30 keV in 1-keV steps. When the ratio of the generated X-ray range to the photon mean free path is much smaller than one, the emission X-ray range is equal to the generated X-ray range, but when this ratio is much greater than one, the emission X-ray range is constant and is given by the product of the effective photon mean free path multiplied by the sine of the take-off angle.

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The Computation of the Skirt in VP-SEM OR ESEM With Monte Carlo Simulations

Microscopy and Microanalysis ◽

10.1017/s143192760001480x ◽

1999 ◽

Vol 5 (S2) ◽

pp. 296-297

Author(s):

Raynald Gauvin

Keyword(s):

Monte Carlo ◽

Electron Beam ◽

Beam Energy ◽

Single Scattering ◽

Gas Composition ◽

Monte Carlo Program ◽

Elastic Collisions ◽

Electron Trajectories ◽

Two Factors ◽

Working Distance

It is well known that the interaction of the electron beam with the gas in the VP-SEM or ESEM generate the so-called skirt as a result of the elastic collisions between the electrons and the molecules. Since the electrons in the skirt hit the specimen far away from the electron beam, they degrade the resolution of the analyses performed in the VPSEM or ESEM. However, the magnitude and the shape of the skirt are still a matter of controversy despite the fundamental importance of knowing these two factors. In this context, a Monte Carlo program has been developed to simulate the interaction of the electron beam with a gas as a function of the gas composition, gas pressure, electron beam energy and working distance (in reality, we should talk of the total distance traveled by the electron beam in the gas). This Monte Carlo program used a single scattering approach considering elastic collisions only since energy loss is negligible owing to the low density of the gas. 10 millions electron trajectories have been simulated for each conditions.

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Electron beam induced current study of thin silicon layers on insulator substrate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176228 ◽

1990 ◽

Vol 48 (4) ◽

pp. 618-619

Author(s):

A. Buczkowski ◽

Z. J. Radzimski ◽

J. C. Russ ◽

G. A. Rozgonyi

Keyword(s):

Electron Beam ◽

Energy Loss ◽

Beam Energy ◽

Collection Efficiency ◽

Silicon Layer ◽

Depletion Layer ◽

Incident Electron Energy ◽

Induced Current ◽

Electron Hole ◽

Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

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Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017685x ◽

1990 ◽

Vol 48 (4) ◽

pp. 744-745

Author(s):

D.P. Malta ◽

M.L. Timmons

Keyword(s):

Electron Beam ◽

Beam Energy ◽

Minority Carrier ◽

Diffusion Length ◽

Effective Diffusion ◽

Surface Recombination ◽

Surface Recombination Velocity ◽

Logarithmic Scale ◽

Minority Carrier Diffusion Length ◽

Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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ELECTRON BEAM ENERGY BRANCHING IN OXYGEN

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19797375 ◽

1979 ◽

Vol 40 (C7) ◽

pp. C7-777-C7-778

Author(s):

G. Fournier ◽

J. Bonnet ◽

J. Bridet ◽

J. Fort ◽

D. Pigache

Keyword(s):

Electron Beam ◽

Beam Energy ◽

Electron Beam Energy

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Control of electron beam energy-spread by beam loading effects in a laser-plasma accelerator

Plasma Physics and Controlled Fusion ◽

10.1088/1361-6587/ab7c50 ◽

2020 ◽

Vol 62 (5) ◽

pp. 055004 ◽

Cited By ~ 1

Author(s):

Guangyu Li ◽

Quratul Ain ◽

Song Li ◽

Muhammad Saeed ◽

Daniel Papp ◽

...

Keyword(s):

Electron Beam ◽

Laser Plasma ◽

Beam Energy ◽

Plasma Accelerator ◽

Energy Spread ◽

Electron Beam Energy ◽

Beam Loading ◽

Loading Effects ◽

Laser Plasma Accelerator

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Soft-X-ray spectra of highly charged Au ions in an electron-beam ion trap

Canadian Journal of Physics ◽

10.1139/p00-104 ◽

2001 ◽

Vol 79 (2-3) ◽

pp. 153-162 ◽

Cited By ~ 26

Author(s):

E Träbert ◽

P Beiersdorfer ◽

K B Fournier ◽

S B Utter ◽

K L Wong

Keyword(s):

Electron Beam ◽

Beam Energy ◽

Large Scale ◽

Ion Trap ◽

Electron Beam Energy ◽

X Ray ◽

Maximum Charge ◽

Electron Beam Ion Trap ◽

Atomic Structure Calculations ◽

Structure Calculations

Systematic variation of the electron-beam energy in an electron-beam ion trap has been employed to produce soft-X-ray spectra (20 to 60 Å) of Au with well-defined maximum charge states ranging from Br- to Co-like ions. Guided by large-scale relativistic atomic structure calculations, the strongest Δn = 0 (n = 4 to n' = 4) transitions in Rb- to Cu-like ions (Au42+ Au50+) have been identified. PACS Nos.: 32.30Rj, 39.30+w, 31.50+w, 32.20R

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