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2009
Conference Paper
Titel
Detection of Acidic Substances of H-X Type in Clean Room Air
Abstract
Cavity 'ringdown' spectroscopy is besides ion mobility spectroscopy another technique for the online detection of volatile compounds in air. Based on absorption spectroscopy, cavity 'ringdown' spectroscopy (CRDS) works by attuning light from a laser to a wavelength in the infrared spectrum at which a certain contaminant adsorption peak occurs. The concentration is calculated from the time it takes for the light to fade or 'ringdown' within an adsorption cell (cavity) which is filled with the gas to be analyzed. A test setup for generation of airflows contaminated with acids substances of H-X type was build and tested successfully. The setup was used to compare a cavity 'ringdown' spectroscopy with impinger sampling in combination ion chromatography. The developed methods can be used for the evaluation of HF-levels in the clean room air. CDRS can be used to monitor HF-levels under dynamic conditions of local sources continuously.