Deposition and Etching of Thin Films by Means of Beam Plasma Discharge with Tube-Like Electron Beam

The efficiency of energy dissipation caused by the mechanism of turbulent plasma heating from a tube-like electron beam in a electronegative gas is measured calorimetrically. Amorphous Si-layers are deposited from a SiH₄/Ar discharge both on conducting and nonconducting substrates and are analyzed by means of Auger-spectrometry. The velocity and specific energy of etching of SiO₂-layers in a CF₄-plasma are determined. Measured etching velocities of tungsten surfaces biased differently against the space potential provide information on the mechanism of plasma etching in a SF₆-plasma. Simultaneously performed Langmuir-probe measurements permit predictions to be made on the properties of the etching plasma.     

Extended Cylindrical Low-Pressure Arc Discharge Plasma Emitter for Generation of a Radially Diverging Electron Beam

Russian Physics Journal - The paper presents the results of studies of processes of generation of a beam-plasma formation in an extended cylindrical hollow mesh anode with a diameter of 115 mm and...     

Plasma Beam Discharge in Carbon Dioxide

The paper deals with the dissociation of carbon dioxide in nonequilibrium plasma of a stationary plasma-beam discharge. Experimental results of spectroscopic and probe measurements of plasma parameters are given. Moreover, a mass-spectrometric analysis of gaseous products of the chemical reactions is presented. In addition the measurement of the deposition rate of solid products by means of a quartz oscillator is described. The results show that plasma beam discharge is an effective tool for inducing plasma-chemical reactions.     

Measurements of the Cathode Fall Characteristics in an Electron Beam Ionized Discharge

Measurements of cathode fall characteristics and of the influence of the cathode fall on the discharge properties of an electron beam ionized discharge (EBD) are reported. Gases investigated included methane, nitrogen, and argon. The cathode fall voltage was found to be a function of discharge current, voltage, gas type and pressure, and the rate of external ionization. At low discharge voltages, the cathode sheath region was found to require microseconds to get established. Added attaching gases had little influence on the cathode fall. Extrapolating to high rates of external ionization, the cathode fall voltage still can be expected to be hundreds of volts for the gases investigated.     

Probe Measurements in a Beam Plasma Discharge

The influence of the beam energy and beam current density on the parameters of the plasma is investigated. The efficiency of carrier generation by collective interactions (Langmuir-oscillations) is compared with that by the single collision mechanism. The additional negative charging of the static probe caused by the beam electrons is used for the determination of the beam electron density.     

The Impact of Direct Ionization by Beam Electrons on the Electron Kinetics of the Beam Discharge Plasma in Molecular Hydrogen

In a recent paper the stationary beam plasma discharge in partially dissociated hydrogen was investigated where the electron component was described by the Boltzmann equation for a mixture of atomic and molecular hydrogen and the main heavy charged and neutral particles by balance equations. It was assumed that, via the quasilinear beam plasma interaction, the electron beam produces only the turbulent electric field whilst an additional production of plasma electrons due to direct ionization by the beam and thus a direct influence on the balances of charge carriers were neglected. Now the additional production of plasma electrons due to direct ionization by the beam is studied on the basis of a generalized Boltzmann equation but for the simpler model of a purely molecular hydrogen plasma. For experimentally obtainable values of the turbulence energy density, beam energy, beam ionization degree and electron life time the calculation of the electron energy distribution function and of the direct beam contribution to the electron particle balance shows a marked influence of the direct beam ionization with increasing degree of beam ionization.     

Investigating a Plasma Lens with the Initiation of Electron-Beam Discharge

Physics of Particles and Nuclei Letters - Currently, work is underway to create laser accelerators with beam focusing by plasma lenses. For effective focusing, it is necessary to investigate at...     

Interaction of an Electron Beam with Electromagnetic Waves in a Rectangular Plasma Waveguide

We study the interaction of a rectilinear nonrelativistic electron beam with a solid-state plasma in a rectangular metal waveguide, as well as wave processes in a plasma waveguide of rectangular cross section in the absence of an electron beam. It is shown that in such a system, space-charge waves of an electron beam, which propagate along a semiconductor boundary, become unstable in a wide frequency band.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 3, pp. 219–227, March 2005.     

X-Ray Bremsstrahlung Measurements of an Intense Relativistic Electron Beam Propagating in a Plasma

Information on the peak electron energy, angular spread, and current density of a relativistic electron beam propagating in a plasma column is obtained from measurements of two-absorber transmission ratios, anistropy, and intensity, respectively, of x-ray bremsstrahlung from thin target foils in the plasma. Measurements indicate a 10% loss in peak electron energy and a factor of two loss in peak beam intensity over the distance of the plasma column, and show a large angular spread in the beam.     

Submicrosecond Pulsed Electron Beam Formation in Electron Sources and Accelerators with Plasma Emitters

The most popular methods for submicrosecond electron beam generation and physical processes underlying electron extraction from plasma in plasma emitters are considered. Electron sources and accelerators developed on the basis of plasma emitters allow pulsed beams with currents from tens to 10³ A and current densities of several amperes per square centimeter, pulse durations of hundreds of nanoseconds, and high repetition rates to be generated.     

Spectroscopic Investigation of a Double Discharge Pulsed Electron Beam Generator

ABSTRACT

The wide range of applications of the plasma-based electron beam generator make it necessary to diagnose the device with a noninterfering method. The results of experimental and modeling studies of neutral helium and hydrogen beta spectral lines emitted from the double discharge pulsed electron beam generator are presented in this paper. Neutral helium lines emitted from the plasma in the pressure range 0.1–0.4 torr are studied and compared with results of the collisional radiative model. The duration of the electron beam is shorter than 100 ns, and the peak current intensity is of order amperes. The full width at half maximum of the H _β spectral line is used for the determination of the plasma electron density, found as 3.16 × 10²¹ m^?3 at 0.3 torr, and good agreement is obtained by comparing with the full computer simulation method.     

Measurement of Electron Emission Spectra from Micropinch Discharge Plasma

Physics of Atomic Nuclei - In this paper, we describe a small-size magnetic spectrometer of electrons that allowed studying the spectral composition of electron emission in the energy range of...     

Interaction of a Relativistic Electron Beam with a Plasma

The dispersion relation for the interaction of a relativistic electron beam in a thermal plasma, in the absence of an external magnetic field, is studied. It is shown that there are two distinct beam-plasma branches present, and that one of them couples to the electromagnetic eigenmode of the beam-plasma system with a magnetic field and a Poynting flux associated with it. It is also shown that these branches can couple together.     

Microsecond Electron Beam Source with Electron Energy Up to 400 Kev and Plasma Anode

Russian Physics Journal - A new high-power source of electrons with plasma anode for producing high-current microsecond electron beams with electron energy up to 400 keV has been developed,...     

Study of the Z-Pinch Plasma Initiated by the Electron Beam

A lot of activities are carried out to develop compact laser accelerators. The transportation and focusing of beams in Z-pinch-type discharges, which requires thorough investigations into methods for the formation of these discharges, are important problems to be solved. At the ITEP, an experimental setup [1] is constructed to study Z-pinch plasma dynamics when the discharge is initiated by an electron beam. The first results of the experimental and numerical investigations show that development of the discharge initiated by an electron beam differs considerably from the ordinary Z-pinch formation process.     

On the Question of Increasing Maxwellization of the Electron Energy Distribution Function due to Electron — Electron Interaction with Growing Ionization Degree in the Beam Discharge Plasma

The question of the establishment of an almost complete Maxwellian energy distribution of the electrons in a given discharge plasma is of importance, especially under the aspect of a more convenient determination of transport and rate coefficients. In [5] an energy space averaged criterion for the establishment of such a structure of the electron energy distribution function in the stationary beam discharge plasma of molecular gases was formulated from a heuristic point of view. This paper investigates this question in detail starting from the adequate Boltzmann equation of such plasmas. Energy resolved conditions for the establishment of an almost complete Maxwellian distribution are derived from the kinetic equation. Using one of these conditions, the formal derivation of the mentioned averaged condition is performed and its limitations are shown. The fulfilment of the energy resolved and of the averaged conditions are illustrated and discussed using solutions of the kinetic equation in purely molecular hydrogen for two parameter sets yielding larger and smaller deviations of the real distribution function from the Maxwellian form.