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Title: An improved pulse-line accelerator-driven, intense current-density, and high-brightness pseudospark electron beam

Abstract

A high-voltage (200 kV), high current-density, low-emittance (23 {pi}{center_dot}mm mrd), high-brightness (8 {times} 10{sup 10} A/(mrd){sup 2}) electron beam was generated in a pseudospark chamber filled with 15 Pa nitrogen and driven by a modified pulse line accelerator. The beam ejected with {le}1-mm diameter, 2.2-kA beam current, 400-ns pulse length, and about 20 cm propagation distance. Exposure of 10 shots on the same film produced a hole of 1.6-mm diameter at 7 cm downstream of the anode, and showed its good reproducibility. After 60 shots, it was observed that almost no destructive damage traces were left on the surfaces of the various electrodes and insulators of the pseudospark discharge chamber. It was experimentally found that the quality of the pseudospark electron beam remains very high, even at high voltages (of several hundred kilovolts), similar to low voltages, and is much better than the quality of the cold-cathode electron beams.

Authors:
; ; ;  [1]
  1. Shanghai Inst. of Optics and Fine Mechanics (China)
Publication Date:
OSTI Identifier:
244956
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Transactions on Plasma Science; Journal Volume: 24; Journal Issue: 1; Other Information: PBD: Feb 1996
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; ELECTRON BEAMS; BEAM PRODUCTION; CURRENT DENSITY; BEAM EMITTANCE; BRIGHTNESS; ELECTRIC DISCHARGES; ELECTRIC POTENTIAL; EXPERIMENTAL DATA

Citation Formats

Zhu, J., Wang, Z., Zhang, L., and Wang, M. An improved pulse-line accelerator-driven, intense current-density, and high-brightness pseudospark electron beam. United States: N. p., 1996. Web.
Zhu, J., Wang, Z., Zhang, L., & Wang, M. An improved pulse-line accelerator-driven, intense current-density, and high-brightness pseudospark electron beam. United States.
Zhu, J., Wang, Z., Zhang, L., and Wang, M. Thu . "An improved pulse-line accelerator-driven, intense current-density, and high-brightness pseudospark electron beam". United States. doi:.
@article{osti_244956,
title = {An improved pulse-line accelerator-driven, intense current-density, and high-brightness pseudospark electron beam},
author = {Zhu, J. and Wang, Z. and Zhang, L. and Wang, M.},
abstractNote = {A high-voltage (200 kV), high current-density, low-emittance (23 {pi}{center_dot}mm mrd), high-brightness (8 {times} 10{sup 10} A/(mrd){sup 2}) electron beam was generated in a pseudospark chamber filled with 15 Pa nitrogen and driven by a modified pulse line accelerator. The beam ejected with {le}1-mm diameter, 2.2-kA beam current, 400-ns pulse length, and about 20 cm propagation distance. Exposure of 10 shots on the same film produced a hole of 1.6-mm diameter at 7 cm downstream of the anode, and showed its good reproducibility. After 60 shots, it was observed that almost no destructive damage traces were left on the surfaces of the various electrodes and insulators of the pseudospark discharge chamber. It was experimentally found that the quality of the pseudospark electron beam remains very high, even at high voltages (of several hundred kilovolts), similar to low voltages, and is much better than the quality of the cold-cathode electron beams.},
doi = {},
journal = {IEEE Transactions on Plasma Science},
number = 1,
volume = 24,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 1996},
month = {Thu Feb 01 00:00:00 EST 1996}
}
  • A high power (200KV), intense current density, low emittance (71mmmrad), high brightness (8x10{sup 10}A/m rad) electron beam was generated in the 10cm long, high-voltage-resistive multi-gap hollow cathode pseudospark chamber filled with 15pa nitrogen and driven by an improved pulse line accelerator. The beam was ejected with the 1mm diameter, the 2.2KA beam current, and the 400ns pulse length, and could propagated 20cm in the drift tube. At a distance of 5cm from the anode it penetrated consecutively an acid-sensitive discoloring film and a 0.05mm-thick copper foil both stuck closely, left 0.6mm and 0.3mm holes on them, respectively. That 10 shotsmore » on an acid-sensitive film produced a hole of 1.6mm at 7cm downstream of anode showed its good repeatability. After 60 shots the pseudospark discharge chamber was disassembled and observed that almost no destructive damage traces left on the surfaces of its various electrodes and insulators. But on almost all the surfaces of changeable central hole parts installed on intermediate electrodes there are traces of electron emission from the sides facing the anode and of bombardment on the sides facing the cathode, in contrast with which on the front- and back-surfaces of hollow cathode no visible traces of electron emission from then was observed. In addition, there were different tints, strip-like regions on the side of anode facing the cathode. Another interesting phenomenon was that there were a set of concentric circular or elliptical ring pattern on the acid-sensitive discoloring film got at 5cm from the anode and observed tinder a metallograph. It seems that the pseudospark electron beam is Laminar beam i.e, being possessed of a multi-layer structure, at least in the case of multi-gap pseudospark discharge chamber. It was found experimentally that the quality of pseudospark electron beam is much better than that of the cold-cathode electron beam.« less
  • High brightness ([similar to]10[sup 10] A/m[sup 2] rad[sup 2]), high power density ([similar to]10[sup 10] W/cm[sup 2]) electron beams have been generated by the mating of a hollow-cathode discharge device operating in the pseudospark regime to the output of a high power pulse line accelerator. Very small diameter ([similar to]1 mm) electron beams with currents in the range 500--1000 A and energies in the range 150--300 keV have been generated with effective emittances estimated to be at or below 170 mm mrad. Such emittances are comparable to those achieved in conventional electron beam sources at current densities several orders ofmore » magnitude lower than those observed in these experiments.« less
  • Emittance and energy measurements have been performed on a high-brightness electron beam ([gt]10[sup 10] A/m[sup 2] rad[sup 2]) with diameter in the range 1--3 mm and energy in the range 150--170 keV. This electron beam is generated by the mating of a hollow-cathode discharge device operating in the pseudospark regime to the output of a high-power pulse line accelerator. The measured effective emittance lies in the range between 30 and 90 mm mrad and increases with axial distance. Electron energy measurements indicate that the high-energy electrons are generated during the first 20--30 ns of the discharge. Both the emittance andmore » energy experiments were performed at two different ambient argon gas pressures (92 and 152 mtorr). Beam expansion as a function of axial position has also been studied and a lower bound on the beam brightness has been obtained.« less
  • The first time-integrated root mean square (rms) emittance measurement of a pseudospark-produced electron beam is presented. From a six-gap pseudospark chamber with argon working gas, {similar to}10 Hz repetitive pulsed electron beams of average energy {similar to}20 keV, peak current {similar to}50 A, and pulse duration {similar to}10 ns are extracted into a drift tube. A typical value of measured rms emittance is found to be {epsilon}{approx}55 mm mrad, yielding a normalized rms emittance of {epsilon}{sub {ital n}}{approx}15 mm mrad. The normalized brightness of the beam is then estimated to be {ital B}{sub {ital n}}{approx}4{times}10{sup 10} A/(m{sup 2} rad{sup 2}more » ).« less
  • A high-brightness electron beam produced by a six-gap pseudospark chamber operated in 5--25 kV voltage and 30--70 mTorr pressure ranges is experimentally investigated. The electron beam of current 150 A at an average energy of 20 keV and pulse duration of 10 nsec is extracted with a repetitive frequency of {similar to}10 Hz. The electron-beam current scales linearly with the breakdown voltage and about 20% of the stored energy is converted into the total beam energy. The time-integrated rms emittance of the electron beam is measured, and a typical value is found to be 65 mm mrad, yielding a normalizedmore » brightness of the beam {ital B}{sub {ital n}}{approx}2{times}10{sup 10} A/(m{sup 2} rad{sup 2}).« less