CAFE: a new, improved non-resonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde [article]

Jason M. St. Clair, Andrew K. Swanson, Steven A. Bailey, Thomas F. Hanisco, Maryland Shared Open Access Repository, Maryland Shared Open Access Repository
2019
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
more » ... ution 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.
doi:10.13016/m2zlkt-pxrr fatcat:ssjc5q6nk5h75comlpjjfr675m