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UP: Umweltphysik

UP 12: Poster: Atmosph
ärische Spurengase und Aerosole: Instrumentelles

UP 12.2: Poster

Tuesday, March 14, 2006, 14:00–16:00, C

Improvement of the Detection Limit of Active-DOAS-Measurements by use of fibre coupled light source — •André Merten and Ulrich Platt — Institut für Umweltphysik, Heidelberg

In active DOAS-measurements, the minimum detectable optical density and thus the detection limit for trace gases are primarily determined by the spectral stability of the light source e.g. a Xenon high-pressure lamp. This is particularly important in spectral ranges where Xe-lines exist. Due to the large temperature gradient and turbulent flow inside the arc these spectral structures strongly vary with time and across the arc of the Xe-high pressure lamp. The use of fibre coupled Xe-light source together with a mathematical treatment reduces the residual structures up to a magnitude. With this new optical set-up it is possible to design a new type of long-path devices, which are easier to handle and show a larger flux of light.