Trace CH4 Gas Detection Based on an Integrated Spherical Photoacoustic Cell

This paper presents an integrated spherical photoacoustic cell (SPAC) for trace methane (CH4) gas detection. Theoretical analysis and analogue simulations are carried out to analyze the acoustic field distribution of SPAC at resonant non-resonant modes. The finite element simulation results based on COMSOL show that first-order radial frequency second-order angular 24,540 Hz 18,250 Hz, respectively, which good agreements with formula results. SPAC, together a high-speed spectrometer distributed feedback (DFB) laser source, makes up (PA) spectroscopy (PAS) system, is employed CH4 minimum detection limit (MDL) measured be 126.9 parts per billion (ppb) average time 1000 s. proposed has integrated, miniaturized all-optical structure, can used remote long-distance