Miniaturized nonresonant photoacoustic gas analyzer for CO<sub>2</sub> detection
Guangyin Zhang, Min Guo, Xinyu Zhao, Dongyu Cui, Lin Xu, Nan Wang, Rui Ni, Hongchao Qi, Jikuan Zhao, Ke Chen
Abstract
Abstract In this letter, a portable trace carbon dioxide (CO 2 ) 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 CO 2 reached 12.7 ppm. The normalized noise‐equivalent absorption coefficient was calculated to be 4.8468 × 10 −9 cm −1 W/Hz 1/2 . With Allan‐Werle deviation analysis, the measurement detection limit for CO 2 improved to 4 ppm with 30 s integration time. As a result, the trace CO 2 instrument based on PAS shows a good performance in long‐term detection.