Quartz-Enhanced Photoacoustic Spectroscopy for Four-Component Gas Detection Based on Two Off-Beam Acoustic Microresonators

Cheng Wang,Xiyu Pang,Zongliang Wang

doi:10.3389/fphy.2020.594326

Cheng Wang, Xiyu Pang + Show 1 more

Open Access

https://doi.org/10.3389/fphy.2020.594326

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Abstract

A compact and portable quartz-enhanced photoacoustic spectroscopy gas sensor was developed for four-component gas detection using two off-beam acoustic microresonators (AMRs). The two AMRs were placed in parallel on opposing sides of a quartz tuning fork (QTF) for photoacoustic signal enhancement. Four distributed feedback (DFB) lasers were connected to the four ends of the two off-beam AMRs using a fiber collimator for photoacoustic signal excitation. Four-component gas sensing was achieved via time-division multiplexing of the DFB laser driver currents. The four-component gas sensing scheme was used to detect acetylene (C2H2) at 1532.83 nm, methane (CH4) at 1653.722 nm, water vapor (H2O) at 1368.597 nm and carbon dioxide (CO2) at 1577.787 nm for feasibility testing. Minimum detection limits of 3.6 ppmv for C2H2, 34.71 ppmv for CH4, 1.09 ppmv for H2O, and 341.18 ppmv for CO2 were obtained, and the linear responses reached 0.9982, 0.9969, 0.99843 and 0.99591 for C2H2, CH4, H2O and CO2, respectively, at 1.5 s intervals.

Highlights

The introduction Quartz-enhanced photoacoustic spectroscopy (QEPAS) was introduced by Kosterev et al in 2002 [1] and offers portability, small volume and an excellent photoacoustic response
We introduced a four-component QEPAS sensor based on an in-house-constructed quartz tuning fork (QTF) photo-acoustic gas cell consisting of two off-beam acoustic microresonator (AMR) and only one QTF
A four-component QEPAS gas sensor was developed based on time-division multiplexing (TDM) of the distributed feedback (DFB) laser drive currents

Summary

Introduction

The introduction Quartz-enhanced photoacoustic spectroscopy (QEPAS) was introduced by Kosterev et al in 2002 [1] and offers portability, small volume and an excellent photoacoustic response. Because of these outstanding performance characteristics [2, 3], QEPAS was widely researched for use in trace gas detection. The on-beam AMR consists of a pair of short metal tubes that are placed on the two sides of a quartz tuning fork (QTF) [8]. The off-beam AMR includes a relatively long tube with a small slit in its center that is placed on one side of the QTF [9]

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