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Title: New method of high brightness ion extraction based on bias electrode

Abstract

It is well known that beam brightness can be enhanced with smaller extraction aperture in plasma ion sources. Reducing aperture size to micrometer scale, however, decreases beam currents significantly since the extraction field cannot be penetrated into the plasma source. In this article, a novel extraction method based on bias electrode is proposed and demonstrated by observing the existence of high current mode with 100 {mu}m aperture diameter. Ion current with a positively biased electrode is increased by an order of magnitude from that of the nonbiased case. Locally converging electrons near positively biased electrode are thought to be the main cause of the high current mode.

Authors:
; ; ;  [1]
  1. Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)
Publication Date:
OSTI Identifier:
20779064
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 77; Journal Issue: 3; Conference: 11. international conference on ion sources, Caen (France), 12-16 Sep 2005; Other Information: DOI: 10.1063/1.2167387; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; APERTURES; BEAM CURRENTS; BRIGHTNESS; ELECTRODES; ELECTRONS; ION BEAMS; ION SOURCES; IONS; PLASMA

Citation Formats

Kim, Y.J., Park, D.H., Jeong, H.S., and Hwang, Y.S.. New method of high brightness ion extraction based on bias electrode. United States: N. p., 2006. Web. doi:10.1063/1.2167387.
Kim, Y.J., Park, D.H., Jeong, H.S., & Hwang, Y.S.. New method of high brightness ion extraction based on bias electrode. United States. doi:10.1063/1.2167387.
Kim, Y.J., Park, D.H., Jeong, H.S., and Hwang, Y.S.. Wed . "New method of high brightness ion extraction based on bias electrode". United States. doi:10.1063/1.2167387.
@article{osti_20779064,
title = {New method of high brightness ion extraction based on bias electrode},
author = {Kim, Y.J. and Park, D.H. and Jeong, H.S. and Hwang, Y.S.},
abstractNote = {It is well known that beam brightness can be enhanced with smaller extraction aperture in plasma ion sources. Reducing aperture size to micrometer scale, however, decreases beam currents significantly since the extraction field cannot be penetrated into the plasma source. In this article, a novel extraction method based on bias electrode is proposed and demonstrated by observing the existence of high current mode with 100 {mu}m aperture diameter. Ion current with a positively biased electrode is increased by an order of magnitude from that of the nonbiased case. Locally converging electrons near positively biased electrode are thought to be the main cause of the high current mode.},
doi = {10.1063/1.2167387},
journal = {Review of Scientific Instruments},
number = 3,
volume = 77,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
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  • The effect of the plasma electrode bias voltage in the negative ion sources is modeled and investigated with one-dimensional plasma simulation. A particle-in-cell (PIC) method is applied to simulate the motion of charged particles in their self-consistent electric field. In the simulation, the electron current density is fixed to produce the bias voltage. The tendency of current-voltage characteristics obtained in the simulation show agreement with the one obtained from a simple probe theory. In addition, the H{sup -} ion density peak appears at the bias voltage close to the plasma potential as observed in the experiment. The physical mechanism ofmore » this peak H{sup -} ion density is discussed.« less
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