QEPAS detector for rapid spectral measurements

A quartz enhanced photoacoustic spectroscopy sensor designed for fast response was used in combination with a pulsed external cavity quantum cascade laser to rapidly acquire gas absorption data over the 1196-1281 cm(-1) spectral range. The system was used to measure concentrations of water vapor, pentafluoroethane (freon-125), acetone, and ethanol both individually and in combined mixtures. The precision achieved for freon-125 concentration in a single 1.1 s long spectral scan is 13 ppbv.