Relevance of Volume and Surface Plasma Generation of Negative Ions in Gas Discharges
- Brookhaven Technology Group, Inc., NY (United States)
The relative contribution of volume and surface-plasma generation in emission of H- ions in gas discharge sources is analyzed. At the present time, it is generally accepted that surface-plasma generation of extracted H- ions dominates over volume processes in discharges with admixture of cesium or other catalysts with low ionization potential. We will attract attention to the evidence, that surface-plasma generation can be significantly enhanced in high density discharges without cesium after electrode activation by high temperature conditioning in discharge. With this optimization of conditions for surface-plasma generation of emitted H-, an emission current density was increased up to {approx}1 A/m2 in discharges without cesium. Diffusion of impurities with low ionization potential can be the reason for the observed enhancement of H- emission. Such optimization allows considerable improvement of H-/D- source characteristics. Volume generation of extracted H- in high density discharges is suppressed by the high level of gas dissociation.
- OSTI ID:
- 20630794
- Journal Information:
- AIP Conference Proceedings, Vol. 763, Issue 1; Conference: 10. international symposium on production and neutralization of negative ions and beams, Kiev (Ukraine), 14-17 Sep 2004; Other Information: DOI: 10.1063/1.1908288; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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