Cavity-enhanced absorption spectroscopy of methane at 1.73 μm

Barry, Hugh R.; Corner, L.; Hancock, Gus; Peverall, R.; Ritchie, Grant A. D.

doi:10.1016/s0009-2614(00)01388-9

Cited by 30 publications

(16 citation statements)

References 19 publications

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“…(6) with Beer-Lambert law, one may conclude that the absorption path length of the transmission signals is enhanced by a factor 4F c /π. It is worth noting that the enhancement factor of a planar FPC is 2F/π [25,26] where F is the finesse of the planar FPC [27]. Considering the different definitions of the finesses F c and F, the effective absorption path length of the planar and confocal FPC are the same.…”

Section: High Sensitivity From Back Cavity Mirror Signalsmentioning

confidence: 99%

High-sensitivity, large dynamic range, auto-calibration methane optical sensor using a short confocal Fabry–Perot cavity

Dong

Yin

et al. 2007

Sensors and Actuators B: Chemical

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Section: High Sensitivity From Back Cavity Mirror Signalsmentioning

confidence: 99%

High-sensitivity, large dynamic range, auto-calibration methane optical sensor using a short confocal Fabry–Perot cavity

Dong

Yin

et al. 2007

Sensors and Actuators B: Chemical

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“…Gas chromatographic methods for the measurement of ambient mixing ratios and the isotopic ratio of methane (and other hydrocarbons) are robust and versatile, but the time per analysis is long, so some effort has gone into developing more real-time and portable systems for specialized applications like plume tracking. Cavity ring-down (and variants like CEAS) 57,58 has begun to be explored for direct real-time spectroscopic measurement of hydrocarbons. Hydrocarbons (especially alkanes) are transparent in the visible and near-UV regions of the spectrum where the best combinations of tunable sources, high quality mirrors, and highly sensitive detectors for cavity ring-down are usually found.…”

Section: Volatile Hydrocarbonsmentioning

confidence: 99%

Solving chemical problems of environmental importance using cavity ring-down spectroscopy

Atkinson

2002

Analyst

104

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Cavity ring-down (CRD) is a sensitive variant of traditional absorption spectroscopy that has found increasing use in a number of chemical measurement applications. This review focuses on applications of cavity ring-down spectroscopy that will be of interest to environmental chemists and analytical chemists working on environmental problems. The applications are classified into direct monitoring approaches, indirect analysis methods and ancillary studies and a differentiation is made between field-tested instruments and proof of principle studies.

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“…Changes in the steady state output power are due to intracavity losses from molecular absorption. [19][20][21] The Harvard ICOS instrument is designed for in situ sampling on high-altitude aircraft in the middle and UTLS and is currently configured to measure the four primary isotopologues of water ͑H 2 O, HDO, H 2 18 O, and H 2 17 O͒ as well as methane ͑CH 4 ͒ in the mid-IR at 6.7 m. In situ airborne sampling requires fast time response, high accuracy and precision, and low contamination from the instrument inlet and plumbing. The Harvard instrument is able to measure water vapor from 1 ppmv to a few thousand ppmv, values typical of the middle and UTLS, as well as simultaneous measurements of the less abundant isotopologues.…”

Section: Introductionmentioning

confidence: 99%

A new cavity based absorption instrument for detection of water isotopologues in the upper troposphere and lower stratosphere

Sayres¹,

Moyer²,

Hanisco³

et al. 2009

Review of Scientific Instruments

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We describe here the Harvard integrated cavity output spectroscopy (ICOS) isotope instrument, a mid-IR infrared spectrometer using ICOS to make in situ measurements of the primary isotopologues of water vapor (H(2)O, HDO, and H(2) (18)O) in the upper troposphere and lower stratosphere (UTLS). The long path length provided by ICOS provides the sensitivity and accuracy necessary to measure these or other trace atmospheric species at concentrations in the ppbv range. The Harvard ICOS isotope instrument has been integrated onto NASA's WB-57 high-altitude research aircraft and to date has flown successfully in four field campaigns from winter 2004-2005 to the present. Off-axis alignment and a fully passive cavity ensure maximum robustness against the vibrationally hostile aircraft environment. The very simple instrument design permitted by off-axis ICOS is also helpful in minimizing contamination necessary for accurate measurements in the dry UTLS region. The instrument is calibrated in the laboratory via two separate water addition systems and crosscalibrated against other instruments. Calibrations have established an accuracy of 5% for all species. The instrument has demonstrated measurement precision of 0.14 ppmv, 0.10 ppbv, and 0.16 ppbv in 4 s averages for H(2)O, HDO, and H(2) (18)O, respectively. At a water vapor mixing ratio of 5 ppmv the isotopologue ratio precision is 50[per thousand] and 30[per thousand] for deltaD and delta(18)O, respectively.

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Cavity-enhanced absorption spectroscopy of methane at 1.73 μm

Cited by 30 publications

References 19 publications

High-sensitivity, large dynamic range, auto-calibration methane optical sensor using a short confocal Fabry–Perot cavity

High-sensitivity, large dynamic range, auto-calibration methane optical sensor using a short confocal Fabry–Perot cavity

Solving chemical problems of environmental importance using cavity ring-down spectroscopy

A new cavity based absorption instrument for detection of water isotopologues in the upper troposphere and lower stratosphere

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