Kiel 2004 – wissenschaftliches Programm
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P: Plasmaphysik
P 17: Postersitzung: Plasma-Wand-Wechselwirkung III, Grundlegende Probleme Theorie II, Schwerionen- Laserplasmen II, Dichte Plasmen II
P 17.1: Poster
Mittwoch, 10. März 2004, 17:45–19:30, Foyer
Studies of line strengths of deuterated hydrocarbons required for density measurements in front of the inner graphite wall of TEXTOR by means of absorption spectroscopy — •I. Möller1, A. Serdioutchenko1, H. Soltwisch1, B. Schweer2, and A. Pospieszczyk2 — 1Institut für Experimentalphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany — 2Institut für Plasmaphysik, FZ Jülich, EURATOM-Association, TEC, 52425 Jülich, Germany
The identification of the intrinsic source of CD4 and CH4 from graphite surfaces is a challenging task in tokamaks. Emission spectroscopy can only provide information on the molecular break-up products, whereas absolute densities of the source molecules can be determined directly by absorption spectroscopy. Therefore an absorption spectrometer system with tunable infrared diode lasers for the detection of CH4, CD4 and their break-up products has been designed for TEXTOR. A rather long absorption path (≈ 100 cm) will be achieved by guiding the laser beam back and forth close to the inner graphite wall of TEXTOR.
TEXTOR is conventionally operated with deuterium as working gas. Therefore, it is necessary to study the respective line strengths for deuterated hydrocarbons, which are not so well documented so far. Often only the line positions are known. Some line strengths of the ν3 band of CD4 at 4.4 µm have been measured in a low-temperature plasma reactor resulting in a detection limit of nCD4 ≈ 1018 m−3. Similar investigations to obtain the line strength of CD3 are ongoing. First calculations have shown that the detection limit is approximately nCD3 ≈ 5 · 1016 m−3 for the ν2 band of CD3 at 21.9 µm.