Aachen PK 2003 – wissenschaftliches Programm

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P: Plasmaphysik

P 4: Poster I

P 4.14: Poster

Montag, 17. März 2003, 17:45–19:15, Foyer

Influence of temperature gradients on the O atom concentration in an oxygen rf–discharge — •A. Mengel, S. Peters, B. Krames, and J. Meichsner — Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, Germany

To determine spatial concentrations of O atoms in an asymmetric capacitively coupled oxygen rf–discharge two-photon laser induced fluorescence spectroscopy (TALIF) is used. With a reference measurement at a spectrally close two-photon resonance of xenon the data are calibrated. For this technique the temperatures of the atomic and molecular oxygen have to be known, taking into account the fine structure levels of the ground state of the O atoms and the quenching of the excited state by the O₂ molecules. Due to the used uncooled electrode system spatial temperature profils are investigated for both species. While the atmospheric O₂–band was utilised to measure the rotational temperature of the O₂–molecules the temperature of the atomic oxygen is determined by the fine structure levels of the ground state. In addition the spatial distribution of the quenching rate is determined in axial and radial direction inside the discharge.