Aachen PK 2003 – wissenschaftliches Programm
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P: Plasmaphysik
P 10: Poster II
P 10.32: Poster
Dienstag, 18. März 2003, 17:30–19:15, Foyer
Detection of hydrocarbons near to the wall of TEXTOR by means of tunable diode laser spectroscopy — •I. Möller1, A. Serdioutchenko1, H. Soltwisch1, B. Schweer2, and A. Pospieszczyk2 — 1Institut für Experimentalphysik, Ruhr-Universtität Bochum, 44780 Bochum, Germany — 2Institut für Plasmaphysik, FZ Jülich, EURATOM-Association, TEC, 52425 Jülich, Germany
An absorption spectrometer with tunable diode lasers for the detection of CH4 and its break-up products has been designed for TEXTOR. A rather long absorption path will be achieved by guiding the laser beam back and forth near to the inner wall of TEXTOR by a retro reflector.
The Zeeman splitting of the molecular lines in the strong magnetic field of TEXTOR (B ≈ 2 T) can be roughly estimated to result in a separation of around 1 cm−1. Due to a low Doppler width at 500 K (≈ 10−3 cm−1) and a large separation between single molecular lines (4-5 cm−1) the individual line components should be resolvable.
For the calculation of the absolute densities the knowledge of the line strength is required but for deuterium compounds in most cases only line positions are known. First calculations have shown that the detection limit of deuterium compounds are around 1012 cm−3 for CD4 and 5 ×1010 cm−3 for CD3. In order to check the reliability of these estimations, a diode laser for CD4 (2250 cm−1 ≈ 4.44 µm) has been acquired and test measurements are in progress.