Broad-beam plasma-cathode electron beam source based on a cathodic arc for beam generation over a wide pulse-width range

Abstract

We describe the design, parameters, and characteristics of a modified wide-aperture, plasma-cathode electron beam source operating in the pressure range of 3 Pa–30 Pa and generating large-radius, low-energy (up to 10 keV) electron beams with a pulse width varying from 0.05 ms to 20 ms and a beam current up to several tens of amperes. A pulsed cathodic arc is used to generate the emission plasma, and a DC accelerating voltage is used to form the electron beam. Modernization of the design and optimization of the operating conditions of the electron source have provided a multiple increase in the pulse duration of the electron beam current and the corresponding increase in the beam energy per pulse, as compared to previously developed pulsed forevacuum electron sources.

Beam-generated plasma formation near a dielectric target irradiated by a pulsed electron beam in the forevacuum pressure range

“…A wide-aperture pulsed, low-energy (up to 8 keV) electron beam 4.5-3 cm in radius was generated by a pulsed, forevacuum-pressure plasma-cathode electron source based on a cathodic arc discharge; see figure 1. The working principles and parameters of this electron source have been described in detail elsewhere [19]. In the present experiment the source was mounted on a vacuum chamber evacuated by a mechanical forevacuum pump, and the desired operating pressure, p = 4-15 Pa, was controlled by the gas (nitrogen) admission rate.…”

Features of Electron Beam Processing of Mn-Zn Ferrites in the Fore-Vacuum Pressure Range in Continuous and Pulse Modes

“…For pulsed mode processing, a wide-aperture fore-vacuum plasma electron source based on an arc discharge, operating in pulsed mode, was used. The design, operational features, and parameters of the source have been described in detail elsewhere [55]. The pulsed electron beam source was positioned on the vacuum chamber, as shown in Figure 3.…”

Generation of beam plasma near a dielectric target irradiated by a pulsed large-radius electron beam in the forevacuum pressure range

“…The pulsed electron beam was generated by a forevacuum plasma-cathode electron source based on an arc discharge. The design and operation features of this e-beam source are presented in [9]. The electron-beam source was mounted on a vacuum chamber (Fig.…”

“…near the ceramic target (at a distance of less than 6 cm from the ceramic target), a sharp increase in the plasma density n i is observed as U a reaches some threshold accelerating voltage U a-th . This threshold voltage U a-th depends on gas pressure p. Due to the operation features of the used pulsed plasma-cathode electron-beam source, at voltage U a < 3.5 kV the emission current I e and the e-beam current density may strongly depend on U a at p > 5 Pa [9]. In addition, it is not always possible to maintain invariable emission current I e at different U a under these conditions (U a < 3.5 kV).…”

“…Forevacuum plasma-cathode electron-beam sources operate at higher gas pressure from about 3 Pa to 100 pascals ("forevacuum pressure range" or "forevacuum") [8,9] as compared to conventional e-beam sources with hot cathodes (thermionic cathodes) and plasma cathodes, which generate electron beams at 10 -4 -10 -1 Pa. Therefore, the forevacuum e-beam sources are attractive for the formation of beam plasma due to the higher density of neutral gas atoms and molecules as compared with conventional pressures (10 -4 -10 -1 Pa).…”