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Title: Effect of Ion Escape Velocity and Conversion Surface Material on H- 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- 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- no direct gain of extracted beam current can be achieved by increasing the converter voltage. The conversion efficiency of H- was observed to vary with converter voltage and follow the existing theories in qualitative manner. We present calculations predicting relative H- yields from different cesiated surfaces with comparison to experimental observations from different types of H- ion sources. Utilizing materials exhibiting negative electron affinity and exposed to UV-light is considered for Cesium-free H-/D- production.

Authors:
 [1];  [1];  [1];  [1];  [2];  [2];  [2];  [2];  [3]
  1. University of Jyvaskyla
  2. Los Alamos National Laboratory (LANL)
  3. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1025838
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 2nd International Symposium on Negative Ions, Beams and Sources, Takayama, Japan, 20101116, 20101119
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AFFINITY; ANIONS; BEAM CURRENTS; EFFICIENCY; ION SOURCES; NEUTRONS; PRODUCTION; VELOCITY; WORK FUNCTIONS

Citation Formats

Tarvainen, Olli, Kalvas, T., Komppula, J., Koivisto, H., Geros, E., Stelzer, J., Rouleau, G., Johnson, K.F., and Carmichael, Justin R. Effect of Ion Escape Velocity and Conversion Surface Material on H- Production. United States: N. p., 2011. Web.
Tarvainen, Olli, Kalvas, T., Komppula, J., Koivisto, H., Geros, E., Stelzer, J., Rouleau, G., Johnson, K.F., & Carmichael, Justin R. Effect of Ion Escape Velocity and Conversion Surface Material on H- Production. United States.
Tarvainen, Olli, Kalvas, T., Komppula, J., Koivisto, H., Geros, E., Stelzer, J., Rouleau, G., Johnson, K.F., and Carmichael, Justin R. Sat . "Effect of Ion Escape Velocity and Conversion Surface Material on H- Production". United States.
@article{osti_1025838,
title = {Effect of Ion Escape Velocity and Conversion Surface Material on H- Production},
author = {Tarvainen, Olli and Kalvas, T. and Komppula, J. and Koivisto, H. and Geros, E. and Stelzer, J. and Rouleau, G. and Johnson, K.F. and Carmichael, Justin R},
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- 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- no direct gain of extracted beam current can be achieved by increasing the converter voltage. The conversion efficiency of H- was observed to vary with converter voltage and follow the existing theories in qualitative manner. We present calculations predicting relative H- yields from different cesiated surfaces with comparison to experimental observations from different types of H- ion sources. Utilizing materials exhibiting negative electron affinity and exposed to UV-light is considered for Cesium-free H-/D- production.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {1}
}

Conference:
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