Miniaturized nonresonant photoacoustic gas analyzer for CO2 detection

Abstract

AbstractIn this letter, a portable trace carbon dioxide (CO2) measurement instrument based on photoacoustic spectroscopy (PAS) was proposed and designed. The nonresonance PA cell (PAC) including a cooper tube with 251.2 μl was designed. Two condenser microphones were used to measure the PA signal simultaneously. The center wavelength of the distributed feedback laser was chosen to 2004 nm. Within 1 s integral time, the detection limit for CO2 reached 12.7 ppm. The normalized noise‐equivalent absorption coefficient was calculated to be 4.8468 × 10−9 cm−1W/Hz1/2. With Allan‐Werle deviation analysis, the measurement detection limit for CO2 improved to 4 ppm with 30 s integration time. As a result, the trace CO2 instrument based on PAS shows a good performance in long‐term detection.