Photoakustischer Detektor mit zwei Strahlengängen für das Anregungslicht

WO 2008116654 A1 UPAB: 20081018 NOVELTY - The detector has light sources e.g. infrared emitters (1a, 1b), for providing light having same intensities while retaining same spectral distribution. Beam paths are allocated to the light sources, where a different absorption of light occurs in the beam paths in selected wavelength regions. A polygonal mirror (4) alternately supplies the light from the beam paths to a photoacoustic measuring cell (6). The intensities of the light sources are constant such that temporal change of the light sources does not generate a photoacoustic signal, which distorts measurement of gas. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for determining concentration of an analyte in a photoacoustic measuring cell. USE - Photoacoustic detector for measuring and monitoring concentration of gaseous air pollutants in air or contaminants in a process gas and for determining concentration of an analyte in a photoacoustic measuring cell. ADVANTAGE - The detector is designed such that it has high selectivity for measurement of the gas even when broadband and inexpensive light sources are utilized