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Title: Effect of Ion Escape Velocity and Conversion Surface Material on H{sup -} Production

Abstract

According to generally accepted models surface production of negative ions depends on ion escape velocity and work function of the surface. We have conducted an experimental study addressing the role of the ion escape velocity on H{sup -} production. A converter-type ion source at Los Alamos Neutron Science Center was employed for the experiment. The ion escape velocity was affected by varying the bias voltage of the converter electrode. It was observed that due to enhanced stripping of H{sup -} no direct gain of extracted beam current can be achieved by increasing the converter voltage. The conversion efficiency of H{sup -} was observed to vary with converter voltage and follow the existing theories in qualitative manner. We present calculations predicting relative H{sup -} yields from different cesiated surfaces with comparison to experimental observations from different types of H{sup -} ion sources. Utilizing materials exhibiting negative electron affinity and exposed to UV-light is considered for Cesium-free H{sup -}/D{sup -} production.

Authors:
 [1];  [2]; ; ;  [1]; ; ; ;  [3];  [4]
  1. University of Jyvaeskylae, Department of Physics, P.O. Box 35 (YFL) 40500 Jyvaeskylae (Finland)
  2. (United States)
  3. Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico, 87545 (United States)
  4. Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee, 37831 (United States)
Publication Date:
OSTI Identifier:
21611655
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1390; Journal Issue: 1; Conference: 2. international symposium on negative ions, beams and sources, Takayama City (Japan), 16-19 Nov 2010; Other Information: DOI: 10.1063/1.3637381; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 74 ATOMIC AND MOLECULAR PHYSICS; 07 ISOTOPES AND RADIATION SOURCES; AFFINITY; BEAM CURRENTS; CESIUM; COMPARATIVE EVALUATIONS; CONVERSION; DEUTERIUM IONS; ELECTRIC POTENTIAL; ELECTRODES; GAIN; HYDROGEN IONS 1 MINUS; ION SOURCES; PLASMA PRODUCTION; STRIPPING; SURFACES; ULTRAVIOLET RADIATION; VELOCITY; WORK FUNCTIONS; ALKALI METALS; AMPLIFICATION; ANIONS; CHARGED PARTICLES; CURRENTS; DIRECT REACTIONS; ELECTROMAGNETIC RADIATION; ELEMENTS; EVALUATION; FUNCTIONS; HYDROGEN IONS; IONS; METALS; NUCLEAR REACTIONS; RADIATIONS; TRANSFER REACTIONS

Citation Formats

Tarvainen, O., Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico, 87545, Kalvas, T., Komppula, J., Koivisto, H., Geros, E., Stelzer, J., Rouleau, G., Johnson, K. F., and Carmichael, J. Effect of Ion Escape Velocity and Conversion Surface Material on H{sup -} Production. United States: N. p., 2011. Web. doi:10.1063/1.3637381.
Tarvainen, O., Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico, 87545, Kalvas, T., Komppula, J., Koivisto, H., Geros, E., Stelzer, J., Rouleau, G., Johnson, K. F., & Carmichael, J. Effect of Ion Escape Velocity and Conversion Surface Material on H{sup -} Production. United States. doi:10.1063/1.3637381.
Tarvainen, O., Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico, 87545, Kalvas, T., Komppula, J., Koivisto, H., Geros, E., Stelzer, J., Rouleau, G., Johnson, K. F., and Carmichael, J. Mon . "Effect of Ion Escape Velocity and Conversion Surface Material on H{sup -} Production". United States. doi:10.1063/1.3637381.
@article{osti_21611655,
title = {Effect of Ion Escape Velocity and Conversion Surface Material on H{sup -} Production},
author = {Tarvainen, O. and Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico, 87545 and Kalvas, T. and Komppula, J. and Koivisto, H. and Geros, E. and Stelzer, J. and Rouleau, G. and Johnson, K. F. and Carmichael, J.},
abstractNote = {According to generally accepted models surface production of negative ions depends on ion escape velocity and work function of the surface. We have conducted an experimental study addressing the role of the ion escape velocity on H{sup -} production. A converter-type ion source at Los Alamos Neutron Science Center was employed for the experiment. The ion escape velocity was affected by varying the bias voltage of the converter electrode. It was observed that due to enhanced stripping of H{sup -} no direct gain of extracted beam current can be achieved by increasing the converter voltage. The conversion efficiency of H{sup -} was observed to vary with converter voltage and follow the existing theories in qualitative manner. We present calculations predicting relative H{sup -} yields from different cesiated surfaces with comparison to experimental observations from different types of H{sup -} ion sources. Utilizing materials exhibiting negative electron affinity and exposed to UV-light is considered for Cesium-free H{sup -}/D{sup -} production.},
doi = {10.1063/1.3637381},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1390,
place = {United States},
year = {2011},
month = {9}
}