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Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes

Abstract

Backscattered electrons from anodes with high-atomic-number substrates cause early-time anode-plasma formation from the surface layer leading to faster, more intense electron beam pinching, and lower diode impedance. A simple derivation of Child-Langmuir current from a thin hollow cathode shows the same dependence on the diode aspect ratio as critical current. Using this fact, it is shown that the diode voltage and current follow relativistic Child-Langmuir theory until the anode plasma is formed, and then follows critical current after the beam pinches. With thin hollow cathodes, electron beam pinching can be suppressed at low voltages (< 800 kV) even for high currents and high-atomic-number anodes. Electron beam pinching can also be suppressed at high voltages for low-atomic-number anodes as long as the electron current densities remain below the plasma turn-on threshold. (author). 8 figs., 2 refs.
Authors:
Cooperstein, G; Mosher, D; Stephanakis, S J; Weber, B V; Young, F C; [1]  Swanekamp, S B [2] 
  1. Naval Research Laboratory, Washington, DC (United States)
  2. JAYCOR, Vienna, VA (United States)
Publication Date:
Dec 31, 1996
Product Type:
Conference
Report Number:
INIS-CZ-0003; CONF-960610-
Reference Number:
SCA: 700390; PA: AIX-28:056073; EDB-97:114566; SN: 97001835053
Resource Relation:
Conference: BEAMS `96: 11. international conference on high-power particle beams, Prague (Czech Republic), 10-14 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of Beams `96. Proceedings of the 11th international conference on high power particle beams. Vol. II; Jungwirth, K.; Ullschmied, J. [eds.]; PB: [692] p.
Subject:
70 PLASMA PHYSICS AND FUSION; DIODE TUBES; ELECTRON BEAMS; ALUMINIUM; ANODES; BACKSCATTERING; BEAM PRODUCTION; BEAM PROFILES; ELECTRONS; MEV RANGE 10-100; PINCH EFFECT; TANTALUM; X-RAY RADIOGRAPHY
OSTI ID:
511269
Research Organizations:
Ceskoslovenska Akademie Ved, Prague (Czech Republic). Ustav Fyziky Plazmatu
Country of Origin:
Czech Republic
Language:
English
Other Identifying Numbers:
Other: ON: DE97637209; TRN: CZ9726925056073
Availability:
INIS; OSTI as DE97637209
Submitting Site:
INIS
Size:
pp. 1151-1154
Announcement Date:

Citation Formats

Cooperstein, G, Mosher, D, Stephanakis, S J, Weber, B V, Young, F C, and Swanekamp, S B. Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes. Czech Republic: N. p., 1996. Web.
Cooperstein, G, Mosher, D, Stephanakis, S J, Weber, B V, Young, F C, & Swanekamp, S B. Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes. Czech Republic.
Cooperstein, G, Mosher, D, Stephanakis, S J, Weber, B V, Young, F C, and Swanekamp, S B. 1996. "Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes." Czech Republic.
@misc{etde_511269,
title = {Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes}
author = {Cooperstein, G, Mosher, D, Stephanakis, S J, Weber, B V, Young, F C, and Swanekamp, S B}
abstractNote = {Backscattered electrons from anodes with high-atomic-number substrates cause early-time anode-plasma formation from the surface layer leading to faster, more intense electron beam pinching, and lower diode impedance. A simple derivation of Child-Langmuir current from a thin hollow cathode shows the same dependence on the diode aspect ratio as critical current. Using this fact, it is shown that the diode voltage and current follow relativistic Child-Langmuir theory until the anode plasma is formed, and then follows critical current after the beam pinches. With thin hollow cathodes, electron beam pinching can be suppressed at low voltages (< 800 kV) even for high currents and high-atomic-number anodes. Electron beam pinching can also be suppressed at high voltages for low-atomic-number anodes as long as the electron current densities remain below the plasma turn-on threshold. (author). 8 figs., 2 refs.}
place = {Czech Republic}
year = {1996}
month = {Dec}
}