CAFE: a new, improved non-resonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde
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Author/Creator ORCID
Date
2019-08-30
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Citation of Original Publication
Jason M. St. Clair, et.al, CAFE: a new, improved non-resonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde, Atmos. Meas. Tech., 12, 4581–4590, 2019 https://doi.org/10.5194/amt-12-4581-2019
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Attribution 4.0 International (CC BY 4.0)
Attribution 4.0 International (CC BY 4.0)
Abstract
NASA Compact Airborne Formaldehyde Experiment (CAFE) is a nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde
(HCHO). The instrument is described here with highlighted
improvements from the predecessor instrument, COmpact
Formaldehyde FluorescencE Experiment (COFFEE). CAFE
uses a 480 mW, 80 kHz laser at 355 nm to excite HCHO and
detects the resulting fluorescence in the 420–550 nm range.
The fluorescence is acquired at 5 ns resolution for 500 ns and
the unique time profile of the HCHO fluorescence provides
measurement selectivity. CAFE achieves a 1σ precision of
160 pptv (1 s) and 90 pptv (10 s) for [HCHO] = 0 pptv. The
accuracy of CAFE, using its curve-fitting data processing, is
estimated as ±20 % of [HCHO] + 100 pptv. CAFE has successfully flown on multiple aircraft platforms and is particularly well-suited to high-altitude research aircraft or small
air quality research aircraft where high sensitivity is required
but operator interaction and instrument payload is limited.