Off-axis cavity ringdown spectroscopy: application to atmospheric nitrate radical detection
| Autor: | Douglas S. Baer, R. L. Apodaca, James D. Ayers, William R. Simpson |
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| Rok vydání: | 2005 |
| Předmět: |
Materials science
Absorption spectroscopy Materials Science (miscellaneous) Sensitivity and Specificity Industrial and Manufacturing Engineering law.invention Cavity ring-down spectroscopy Optics law Business and International Management Spectroscopy Absorption (electromagnetic radiation) Diode Detection limit Air Pollutants Nitrates business.industry Atmosphere Lasers Spectrum Analysis Reproducibility of Results Equipment Design Laser Equipment Failure Analysis business Sensitivity (electronics) Environmental Monitoring |
| Zdroj: | Applied optics. 44(33) |
| ISSN: | 1559-128X |
| Popis: | Atmospheric nitrate radicals (NO3) are detected using off-axis cavity ringdown spectroscopy (CRDS) for the first time to our knowledge with a room-temperature continuous-wave (cw) diode laser operating near 662 nm. A prototype instrument was constructed that achieved a 1sigma absorption sensitivity of 5 x 10(-10) cm(-1) Hz(-1/2), corresponding to a 1.4 part per trillion by volume 2sigma detection limit in 4.6 s at 80 degrees C. This sensitivity is a significant improvement over a recent implementation of off-axis cavity-enhanced absorption spectroscopy and comparable to that of the most advanced cw CRDS and pulsed CRDS applications for atmospheric detection of NO3. A comparison of measurements of ambient air in Fairbanks, Alaska, recorded with the off-axis CRDS instrument and a previously characterized conventional cw CRDS instrument showed good agreement (R2 = 0.97). |
| Databáze: | OpenAIRE |
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