Cavity ring-down spectroscopy instrumentation for airborne detection of nitrogen oxides
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Dubé, W. P.
University College Cork
Pulsed laser cavity ring-down spectroscopy (CaRDS) is a highly sensitive method for direct absorption spectroscopy that has been applied to in-situ detection of NO3, N2O5, NO2, NO, and O3, as well as NOx and NOy in the atmosphere from a variety of airborne platforms. CaRDS instruments have traditionally been large and delicate laboratory instruments. The successful leap from laboratory instruments with high maintenance requirements to compact and rugged field instruments for airborne deployment was made possible through the extensive engineering work and new innovations presented in this thesis. The necessary improvements were mainly in the six following areas: 1) Instrument rack design and vibration isolation, 2) Automated aerosol filter changer, 3) Low loss inlet design and flow control, 4) Optical cage design, 5) Clamped/nudged mirror mount, and 6) Purge system improvements. The result was a series of compact, reliable, and rugged field instruments with high sensitivity and accuracy. The first airborne deployment was performed in 2004. The designs have been copied by several other research groups, and airborne measurements with CaRDS instruments are now considered routine.
Cavity ring down , Trace gas detection , Airborne instrumentation , Nitrogen oxides , Atmospheric chemistry
Dubé, W. P. 2018. Cavity ring-down spectroscopy instrumentation for airborne detection of nitrogen oxides. PhD Thesis, University College Cork.