Stuttgart 2012 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 7: Diagnostik (von Niedertemperaturplasmen)
P 7.2: Vortrag
Dienstag, 13. März 2012, 11:00–11:15, V57.01
Quantitative determination of ion densities in hydrogen-nitrogen-argon low-temperature plasmas — •Maik Sode1, Thomas Schwarz-Selinger1, Wolfgang Jacob1, and Holger Kersten2 — 1Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr.2, D-85748 Garching, Germany — 2Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel
Hydrogen-nitrogen-argon discharges are of interest for radiative cooling in fusion edge plasmas with metal walls. Furthermore, they are also suitable for technical processes such as plasma nitriding or passivation of metal surfaces. Ion densities are quantified in a hydrogen-nitrogen-argon admixed ICP plasma by energy-dispersive mass spectrometry. For 1.5 Pa and 200 W the nitrogen fraction is increased while the hydrogen fraction is decreased correspondingly. The argon content is fixed at 1 %. For N2 fractions between 5 % and 60 % the species with the highest ion densities are NH3+, NH4+ and N2H+. The density of primary source gas ions such as N2+, Ar+ or Hx+ are at least one order of magnitude lower. The experimental data are compared to results from a rate equation model. Input parameters are rate coefficients for 29 species, losses to the wall, ne from Langmuir probe measurements and the neutral ammonia content from molecular beam mass spectrometry.