Differential photoacoustic spectroscopy for flow gas detection based on single microphone

Autor: Lujun Fu, Jiangshan Zhang, Yufeng Pan, Ping Lu
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Photoacoustics, Vol 38, Iss , Pp 100624- (2024)
Druh dokumentu: article
ISSN: 2213-5979
DOI: 10.1016/j.pacs.2024.100624
Popis: Differential photoacoustic spectroscopy (PAS) for flow gas detection based on single microphone is innovatively proposed and experimentally demonstrated. Unlike the traditional systems, only one microphone is used to suppress flowing gas noise. Wavelength modulation spectroscopy and second harmonic detection technique are applied in this PAS system with Q-point demodulation for acetylene (C2H2) gas detection. The experiment is conducted at 1 atm and 300 K. Different concentrations and flow rates of C2H2 from 0 sccm to 225 sccm are detected by using nitrogen (N2) as the carrier gas, which indicates that the system can respond well to flowing gases while maintaining the noise at the same level. The system response time decreases to 3.58 s while the gas velocity is 225 sccm. The detection limit of 43.97 ppb with 1 s integration time and normalized noise equivalent absorption (NNEA) coefficient of 4.0 × 10-9 cm-1 W Hz-1/2 is achieved at the flow rate of 225 sccm. The firstly proposed differential PAS based on single microphone greatly simplifies the system structure for flow gas detection, which provides a novel route for development of PAS with significant practical implementation prospects.
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