scholarly journals Automated cavity ring down spectroscopy usage for nitrous oxide emission measurements from soil using recirculation system

2017 ◽  
Author(s):  
Inga Grinfelde ◽  
Kristine Valujeva ◽  
Karina Zaharane ◽  
Laima Berzina
Keyword(s):  
Nitrous Oxide ◽  
Nitrous Oxide Emission ◽  
Cavity Ring Down Spectroscopy ◽  
Recirculation System ◽  
Cavity Ring Down

scholarly journals High-precision measurements of nitrous oxide and methane in air with cavity ring-down spectroscopy at 7.6 μm

2018 ◽  
Author(s):  
Jing Tang ◽  
Bincheng Li ◽  
Jing Wang
Keyword(s):  
Nitrous Oxide ◽  
Continuous Wave ◽  
Central City ◽  
Effect Of Temperature ◽  
Exhaled Breath ◽  
Measurement Sensitivity ◽  
Cavity Ring Down Spectroscopy ◽  
Ch4 And N2o ◽  
Averaging Time ◽  
Cavity Ring Down

Abstract. A high-sensitivity methane (CH4) and nitrous oxide (N2O) sensor based on mid-infrared continuous-wave (cw) cavity ring-down spectroscopy (CRDS) technique was developed for environmental and biomedical trace gas measurements. A tunable external-cavity mode-hop-free (EC-MHF) quantum cascade laser (QCL) operating at 7.4 to 7.8 µm was used as the light source. The effect of temperature fluctuation on the measurement sensitivity of the CRDS experimental setup was analyzed and corrected, and a sensitivity limit of absorption coefficient measurement of 7.38 × 10 10 cm−1 was achieved at 1330.50 cm−1 with an average of 176 measurements, or 26.4-seconds averaging time, and further improved to 1.70 × 10–10 cm−1 with average of 3266 measurements, or 490-seconds averaging time. For the targeted CH4 and N2O absorption lines located at 1298.60 cm−1 and 1327.07 cm−1, with temperature effect correction detection limits of 18.2 pptv and 14.9 pptv were experimentally achieved with 24.9-seconds and 20.5-seconds averaging time, and could be further improved to 3.62 pptv and 4.67 pptv with 513-seconds and 461-seconds averaging time, respectively. Four spectral bands (1298.4 cm−1 to 1298.9 cm−1, 1310.1 cm−1 to 1312.3 cm−1, 1326.5 cm−1 to 1328 cm−1, and 1331.5 cm−1 to 1333 cm−1) in the spectral range from 1295 cm−1 to 1335 cm−1 were selected for the separate and simultaneous measurements of CH4 and N2O under normal atmospheric pressure, and all were in good agreements. The concentrations of CH4 and N2O of atmospheric air collected at different locations and of exhaled breath were measured and analyzed. It was found that raining might have effect on the N2O concentration in out-door open-field air and anaerobic bacteria in water and soil of wetland might significantly increase the CH4 concentration in air. The measured N2O concentration in the central city area was somewhat lower than the reported normal level in open air. Our results demonstrated the temporal and spatial variations of CH4 and N2O in air.

scholarly journals Doppler-free two-photon cavity ring-down spectroscopy of a nitrous oxide ( N2O ) vibrational overtone transition

2020 ◽  
Vol 101 (6) ◽  
Author(s):  
Gang Zhao ◽  
D. Michelle Bailey ◽  
Adam J. Fleisher ◽  
Joseph T. Hodges ◽  
Kevin K. Lehmann
Keyword(s):  
Nitrous Oxide ◽  
Cavity Ring Down Spectroscopy ◽  
Two Photon ◽  
Vibrational Overtone ◽  
Cavity Ring Down

scholarly journals High-precision measurements of nitrous oxide and methane in air with cavity ring-down spectroscopy at 7.6 µm

2019 ◽  
Vol 12 (5) ◽  
pp. 2851-2861 ◽  
Author(s):  
Jing Tang ◽  
Bincheng Li ◽  
Jing Wang
Keyword(s):  
Nitrous Oxide ◽  
Continuous Wave ◽  
Central City ◽  
Effect Of Temperature ◽  
Exhaled Breath ◽  
Measurement Sensitivity ◽  
Cavity Ring Down Spectroscopy ◽  
Ch4 And N2o ◽  
Averaging Time ◽  
Cavity Ring Down

Abstract. A high-sensitivity methane (CH4) and nitrous oxide (N2O) sensor based on mid-infrared continuous-wave (CW) cavity ring-down spectroscopy (CRDS) techniques was developed for environmental and biomedical trace-gas measurements. A tunable external-cavity mode-hop-free (EC-MHF) quantum cascade laser (QCL) operating at 7.4 to 7.8 µm was used as the light source. The effect of temperature fluctuation on the measurement sensitivity of the CRDS experimental setup was analyzed and corrected, and a sensitivity limit of absorption coefficient measurement of 7.2×10-10 cm−1 was achieved at 1330.50 cm−1 with an average of 139 measurements or 21 s averaging time and further improved to 2.3×10-10 cm−1 with an average of 3460 measurements, or 519 s averaging time. For the targeted CH4 and N2O, absorption lines located at 1298.60 and 1327.07 cm−1 with temperature effect correction detection limits of 13 and 11 pptv were experimentally achieved with 10.4 and 10.2 s averaging times and could be further improved to 5 and 9 pptv with 482.5 and 311 s averaging times, respectively. Four spectral bands (1298.4 to 1298.9 cm−1, 1310.1 to 1312.3 cm−1, 1326.5 to 1328 cm−1, and 1331.5 to 1333 cm−1) in the spectral range from 1295 to 1335 cm−1 were selected for the separate and simultaneous measurements of CH4 and N2O under normal atmospheric pressure, and all were in good agreements. The concentrations of CH4 and N2O of atmospheric air collected at different locations and of exhaled breath were measured and analyzed. Continuous measurements of CH4 and N2O concentrations of indoor laboratory air over 45 h were also taken. It was found that anaerobic bacteria in the water and soil of wetlands might significantly increase the CH4 concentration in the air. The measured N2O concentration in the central city area was somewhat lower than the reported normal level in open air. Our results demonstrated the temporal and spatial variations of CH4 and N2O in the air.

On Electronic Type Cavity Ring-Down Spectroscopy

2014 ◽  
Vol 134 (8) ◽  
pp. 243-246
Author(s):  
Yuki Hirabayashi ◽  
Hirokazu Tanimoto ◽  
Yoshinobu Maeda
Keyword(s):  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down
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