Bochum 2015 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 6: Poster Session - Diagnostics

P 6.11: Poster

Montag, 2. März 2015, 16:30–18:30, Foyer Audimax

Improvement of a THz Time Domain Spectroscopy System for Plasma Diagnostics — •Steffen Marius Meier, Tsanko Vaskov Tsankov, Dirk Luggenhölscher, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr-University Bochum, Germany

Terahertz Time Domain Spectroscopy is a non-invasive diagnostic method which uses the advantages of a pico-second radiation pulse with a broad spectral width in the THz range. Frequency dependent phase and amplitude characteristics are measured and allow determination of the complex dielectric function, electron density and collision frequency. In contrast to microwave interferometry, the technique is inherently insensitive to vibrations.

Only a few applications of this new technique are reported in the literature so far. Typical detection threshold densities in small low temperature plasmas are 10¹² cm⁻³. In order to enhance the sensitivity substantially our diagnostic system is currently upgraded from a lock-in frequency of 7.6 kHz to 76 MHz. This should allow for a two order of magnitude reduced threshold. The current status of the project as well as concepts for further improvement will be presented.