Düsseldorf 2007 – scientific programme

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P: Fachverband Plasmaphysik

P 22: Poster

P 22.19: Poster

Thursday, March 22, 2007, 16:30–18:30, Poster A

Optimized investigation technique of RF low-temperature plasma discharges by means of Thomson scattering. — •Victor Gorshelev and Henning Soltwisch — Ruhr-Universität Bochum, Deutschland

Attempts have been made to apply Thomson scattering diagnostics to low temperature plasmas, in particular to RF-coupled discharges. Due to the properties of the investigated reactive plasmas (with comparatively low electron densities of 10¹⁵ m⁻³ - 10¹⁷ m⁻³ and electron temperatures of a few eV, resulting in low scattered light intensity with a rich spectrum of molecular emission lines), the diagnostic system has a special design. High stray light intensity requires usage of a double monochromator.

To reduce the time for the acquisition of a Thomson spectrum, an eight-channel multianode photomultiplier tube is utilised as a detector to simultaneously perform time-resolved photon counting. PMT in combination with a modern PC-based multichannel scaler system serves as a convenient experimental tool. The temporal resolution allows the detection of fluorescence decay. Therefore the detection setup can also be used for measurements of low intensity fluorescence as one expects at low concentrations of the investigated species. The design criteria and technical realization, as well as preliminary results, will be presented.