A Method of Trace Gases Detection Based on Non-resonance Photoacoustic Spectroscopy

It is significantly important for public health protection and environmental monitoring to complete accurate measurement of concentration information of hazardous gases and greenhouse gases. Based on the thermal effect of gas infrared absorption and the acoustic theory of photoacoustic (PA) cell, non-resonant photoacoustic spectroscopy(PAS) is an effective method to monitor gases. The basic principle of PAS is introduced, and the instrumental structure is addressed. The experiment is taken with ammonia as example and water vapor as interference. The responding coefficient of ammonia is calculated, and the output concentration is corrected with water vapor filter by correction method. (paper)