High-current diode with ferroelectric plasma source-assisted hollow anode

Vekselman, V.; Gleizer, J. Z.; Yatom, Shurik; Gurovich, V. Tz.; Krasik, Ya. E.

doi:10.1063/1.3486450

Cited by 3 publications

(1 citation statement)

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“…LIF is widely used as a non-invasive diagnostic for a variety of measurements in plasma [23], including densities of atomic [24,25] and molecular [26][27][28] species, ion/neutral temperatures [29][30][31][32] and ion velocities [33]. The Ar metastable levels are typically used for LIF measurements of neutral velocity distribution functions [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Measurement and reduction of Ar metastable densities by nitrogen admixing in electron beam-generated plasmas

Yatom,

Chopra,

Kondeti

et al. 2023

Plasma Sources Sci. Technol.

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Electron beam (e-beam) generated plasmas are useful for material processing applications such as deposition and etching because the plasmas deliver a large fluence of very low energy of ions to surfaces. Metastable species produced in the beam-region can also transport significant energy to the plasma periphery and surfaces. In this work, we have investigated the spatially resolved density of metastable Ar 1s5 species produced in an Ar and Ar/N2 e-beam generated plasma at pressures of 60-67 mTorr using laser-induced fluorescence (LIF). The experiments provide the first direct measure of absolute density and reduction of Ar 1s5 in an e-beam generated plasma when argon is diluted with nitrogen. These results are consistent with previous predictions of numerical modeling and measurements using optical emission spectroscopy. The present spatially resolved LIF measurements directly quantify the reduction of Ar 1s5 in the e-beam generated plasma by nitrogen admixing. This reduction was observed in the region of the electron beam and in the plasma periphery, where substrates are usually placed. For example, up to a threefold reduction of the density of Ar 1s5 was measured when the argon background was diluted with 15.5% nitrogen at pressure of 60 mTorr. Ar 1s5 reduction is attributed to excitation exchange with nitrogen molecules as well as the cooling of plasma electrons via inelastic collisions with nitrogen molecules.

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Section: Introductionmentioning

confidence: 99%

Measurement and reduction of Ar metastable densities by nitrogen admixing in electron beam-generated plasmas

Yatom,

Chopra,

Kondeti

et al. 2023

Plasma Sources Sci. Technol.

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High-current carbon-epoxy capillary cathode

Gleizer

Queller

Bliokh

et al. 2012

Journal of Applied Physics

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The results of experiments on the reproducible generation of an electron beam having a high current density of up to 300 A/cm2 and a satisfactorily uniform cross-sectional distribution of current density in a ∼200 kV, ∼450 ns vacuum diode with a carbon-epoxy capillary cathode are presented. It was found that the source of the electrons is the plasma formed as a result of flashover inside the capillaries. It is shown that the plasma formation occurs at an electric field ≤15 kV/cm and that the cathode sustains thousands of pulses without degradation in its emission properties. Time- and space-resolved visible light observation and spectroscopy analyses were used to determine the cathode plasma’s density, temperature, and expansion velocity. It was found that the density of the cathode plasma decreases rapidly in relation to the distance from the cathode. In addition, it was found that the main reason for the short-circuiting of the accelerating gap is the formation and expansion of the anode plasma. Finally, it was shown that when an external guiding magnetic field is present, the injection of the electron beam into the drift space with a current amplitude exceeding its critical value changes the radial distribution of the current density of the electron beam because the inner electrons are reflected from the virtual cathode.

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