Photoacoustic Spectroscopy Based Gas Analysers - Brochure

The Method The Photoacoustic Effect PA signal is generated by modulated light with wavelength coinciding with an absorption band of the component to be measured. By absorbing the light, the molecules get into excited state, and relax by converting the energy into heat. Periodic heating via thermal expansion generates a sound wave, which is amplified acoustically by the PA cell as the light is modulated at the resonance frequency of the cell. The PA signal is proportional to the concentration of the analyte over a wide range.