Development of a Mid‐Infrared Photoacoustic Gas Sensor for Multi‐Component Gas Detection

ABSTRACT To reduce the system volume, lower the instrument cost, and achieve highly sensitive multi‐gas measurement, a photoacoustic spectroscopic (PAS) gas detection system based on a non‐resonant photoacoustic (PA) cell was developed. The filter wheel, chopper and non‐resonant PA cell were designed. By comparing the feedback frequencies, the performance of the self‐made chopper and the commercial chopper was evaluated. The two choppers exhibit comparable frequency‐control performance, while the homemade chopper offers a lower cost and a smaller volume. The sensor performance for CO 2 and CH 4 detection was evaluated using the developed miniaturized sensor system. The Allan deviation was used to evaluate the minimum detection limit (MDL) of the sensor system. At an averaging time of 1 s, the MDLs of CO 2 and CH 4 were 1.41 ppmv and 1.61 ppmv, respectively.