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Atmospheric CH4 measurement near a landfill using an ICL-based QEPAS sensor with V-T relaxation self-calibration
Ist Teil von
Sensors and actuators. B, Chemical, 2019-10, Vol.297, p.126753, Article 126753
Ort / Verlag
Lausanne: Elsevier B.V
Erscheinungsjahr
2019
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
•A QEPAS-based sensor with V-T relaxation self-calibration was developed.•A dual-gas detection was realized based on two-mode combined vibration of a QTF.•A self-calibration method for the CH4 V-T relaxation was provided.•The ppb-level self-calibration CH4 sensor has a simple setup and small sensor size.•Continuous measurements near a landfill in Shanxi province, China, were performed.
A quartz-enhanced photoacoustic spectroscopy methane (CH4) sensor with vibrational to translational (V-T) relaxation self-calibration was realized and tested for atmospheric CH4 detection near a landfill. To normalize the influence of H2O vapor on the CH4 energy relaxation rate, CH4 and H2O concentrations were detected simultaneously by means of a frequency division multiplexing technique, in which a custom quartz tuning fork was operated in the fundamental and first overtone combined vibration mode. A continuous wave, thermoelectrically cooled distributed feedback interband cascade laser emitting at 3.3 μm and a near-infrared DFB laser emitting at 1.37 μm were used as the excitation source for CH4 and H2O detection, respectively. A theoretical model of V-T relaxation and self-calibration method were developed to allow this CH4 sensor to have a simple setup and a small sensor size. Continuous field measurements were carried out near the largest sanitary landfill in Shanxi province, China, to demonstrate the stability and ruggedness of the realized CH4 sensor.