Regensburg 2007 – scientific programme
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UP: Fachverband Umweltphysik
UP 16: Atmosphärische Spurengase und Aerosole: Instrumentelles
UP 16.2: Talk
Tuesday, March 27, 2007, 16:30–16:45, H48
Development of a broadband cavity enhanced absorption spectrometer using light emitting diodes designed for the detection of NO3 — •Jan Meinen1, Ulrich Platt2, and Thomas Leisner3 — 1Institut für Physik, Umweltphysik, Technische Universität Ilmenau, 98693 Ilmenau — 2Institut für Umweltphysik, Im Neuenheimer Feld 229, 69120 Heidelberg — 3Atmosphärische Aerosolforschung, Forschungszentrum Karlsruhe GmbH, 76021 Karlsruhe
A new instrument for measuring the trace gas radical NO3 in the ppt region by optical absorption was developed using a cavity enhanced absorption cell (CEAS). The standard tech-nique of CEAS is very vulnerable to aerosol impact and thus not well suited for direct comparison with differential optical absorption spectroscopy (DOAS) instrument. Using a broad-band light source in CEAS provides the feasibility of employ-ing a DOAS approach in the data acquisition and evaluation. The high level of improvement in light-emitting diode (LED) technology affords a LED driven instrument. This novel light source represents a potentially advantageous alternative to common broadband laser sources for a variety of reasons in-cluding low coast, high durability and reduced power con-sumption. The instrument is self calibrating by pulsing the LED in cavity ringdown approach (CRDS) to obtain mirror reflectivity. The design of the instrument and first results from laboratory measurements of NO3 will be discussed.