768 / 2022-03-31 21:37:54

Simultaneous Detection of CH4 And C2H2 Based on Cantilever Enhanced Photoacoustic Spectroscopy

quantitative detection,photoacoustic spectroscopy,cantilever beam enhanced,binary mixture gas,CH4 and C2H2

Cantilever beam enhanced photoacoustic spectroscopy gas detection technology has attracted extensive attention due to its high detection sensitivity, but the quantitative detection of multi-component in mixed gas has not been carried out yet. In this paper, two infrared laser beams with central wavelengths of 1529.16 nm and 1330 nm are coupled into the same optical fiber with a wave combination, and CH₄ and C₂H₂ are quantitatively detected in binary mixture gas CH₄/N₂, C₂H₂/N₂ and ternary mixture gas CH₄/C₂H₂/N₂. Based on the analysis of the cross interference mechanism of infrared absorption S lines, a quantitative detection method of CH₄ and C₂H₂ in CH₄/C₂H₂/N₂. termist mixture was proposed, and the influence of background gas types on PAS signal intensity was analyzed. The results show that, in mixed gas, there is a linear relationship between the pure PAS signal value and gas concentration. For the terrestrial-mixed gas, the total PAS signal can be regarded as the linear superposition of the respective PAS signals of CH₄ and C₂H₂.