Hannover 2016 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 20: Poster Session- Low Temperature Plasmas
P 20.13: Poster
Mittwoch, 2. März 2016, 16:30–19:00, Empore Lichthof
Comparison between measured and modeled densities of negative hydrogen ions in an ICP discharge — •Sofia Cristofaro1,2, Roland Friedl1, and Ursel Fantz1,2 — 1AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg — 2Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching
Creation of negative hydrogen ions in plasma can occur via volume or surface processes. In negative ion sources the more efficient surface production regime is achieved by caesiation of a converter surface, which leads to a transition from volume dominated to surface dominated H− production. This transition is investigated at the laboratory experiment ACCesS (Augsburg Comprehensive Cesium Setup). The plasma parameters of the planar ICP discharge are close to the ones of ion sources. Prior to the investigation of the surface process, a quantification of the volume produced negative hydrogen ions is mandatory: the H− density is measured by a Cavity Ring Down Spectroscopy system (CRDS), while the plasma parameters, like electron temperature and density, are monitored by means of a Langmuir probe. By varying the pressure and the radio-frequency power, the negative ion density has been investigated and the results are interpreted by means of a 0-dimensional model for H−. The eventual isotopic difference between hydrogen and deuterium plasmas has also been investigated.