Design and Characterization of Macroscopic Indirect Photoacoustic Gas Sensor

• Published in: 2022 IEEE Sensors pp. 1 - 4
• Main Authors: Srivastava, Ananya, Tian, Yuanji, Bittner, Achim, Dehe, Alfons
• Format: Conference Proceeding
• Language: English
• Published: IEEE 30-10-2022
• Subjects: CO 2 concentration measurements; gas sensor; Geometrical optics; Length measurement; Loss measurement; Macroscopic PAS; Optical variables measurement; PAS prototypes; Photoacoustic; Prototypes; Stimulated emission; Volume measurement
• ISSN: 2168-9229
• DOI: 10.1109/SENSORS52175.2022.9967215

A macroscopic photoacoustic gas sensing (PAS) system, along with the design considerations, are presented in this paper. The system is based on the indirect PAS principle. The system consists of a black body IR emitter, suitable optical windows for radiation transmission and a highly sensitive detector in the form of a microphone. A first prototype and its optimized version, for the CO 2 PAS measurements, are subsequently developed and characterized. The prototypes are used for CO 2 concentration measurements in the range of 0-5000 ppm. The length of the whole system is 8-15 cm, with the length of the variable measurement volume 5-12 cm. With the 5 cm long measurement volume, 10 ppm resolution is achieved for the second prototype. With the lock-in integration time of 307 seconds, the theoretical limit of detection (LOD) of 37 ppb is achieved.