Gas-phase Raman spectroscopy of non-reacting flows: comparison between free-space and cavity-based spontaneous Raman emission

Weller, Lee; Kuvshinov, Maxim; Hochgreb, Simone

doi:10.1364/ao.58.000c92

Cited by 6 publications

(3 citation statements)

References 53 publications

(63 reference statements)

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“…The rate of laser-induced Stokes photon emission (photons s ) can be described by 43 – 45 : where is the numerical aperture of a lens ( ), c is the speed of light, n is the index of refraction, is Avogadro’s constant, M is the molar concentration, is the Stokes/pump frequency, is the Stokes/pump mode half-width at half maximum, is the differential Raman scattering cross-section (with a dependence 43 , 46 , 47 ), is the pump input power.…”

Section: Steady-state Experimentsmentioning

confidence: 99%

High-frequency measurement of concentration in an isothermal methane–air gas mixture using spontaneous Raman spectroscopy

Rodrigues,

Weller,

De Domenico

et al. 2023

Sci Rep

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A high-frequency (1.5 kHz) spontaneous Raman spectroscopy measurement technique is developed and applied to measure external fluctuations generated in the local concentration of an isothermal binary gas mixture of methane and air. Raman excitation is provided by a high-frequency laser at 527 nm in dual-pulsed mode. The Stokes Raman signal is collected using an EMCCD camera coupled to a high-frequency intensifier as a shutter. The emitted signal is collected over the 596–627 nm wavelength range, which allows for the simultaneous tracking of methane and nitrogen Stokes Q-branch mode signals. Calibration curves are initially obtained for each species ($${\text{CH}}_{4}$$ CH 4 and $${\mathrm{N}}_{2}$$ N 2 ) based on steady-state concentrations, and further corrected during use to detect local unsteady mixture fluctuations at gas pulsation frequencies up to 250 Hz. The main novelty is the demonstration of Raman spectroscopy for the simultaneous multispecies measurement of unsteady concentrations of gas-phase methane and air mixtures using a laser beam with a high-repetition rate, low energy per pulse, combined with a high-frequency intensifier and a single camera.

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Section: Steady-state Experimentsmentioning

confidence: 99%

High-frequency measurement of concentration in an isothermal methane–air gas mixture using spontaneous Raman spectroscopy

Rodrigues,

Weller,

De Domenico

et al. 2023

Sci Rep

Self Cite

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“…Several analytical instrumental techniques are successfully used in the identification of gases. These include infra-red spectroscopy, , mass spectrometry, , Raman spectroscopy, photoacoustic spectroscopy, and using electronic nose systems based on different types of sensor arrays. − Nowadays, electronic nose systems are employed as the primary gas identification means, which typically involve sensor arrays, signal acquisition and processing, pattern recognition, and reference database. The common sensor types utilized in electronic noses are metal oxide semiconductors , and chemiresistive, electrochemical, gravimetric (SAW, BAW, QCM, etc.…”

Section: Introductionmentioning

confidence: 99%

Gas Identification by Simultaneous Permeation through Parallel Membranes: Proof of Concept

Marzouk

Namous

2022

Anal. Chem.

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This paper describes an experimental system for simultaneous permeation of a pressurized test gas through different gas permeable membranes and provides a proof of concept for a novel approach for gas identification/fingerprinting for potential construction of electronic noses. The design, construction, and use of a six-channel system which allows simultaneous gas permeation from a single pressurized gas compartment through six different parallel membranes are presented. The permeated gas is accumulated in confined spaces behind the respective membranes. The rate of gas pressure accumulation behind each membrane is recorded and used as a measure of the gas permeation rate through the membrane. The utilized gas permeable membranes include Teflon AF, silicone rubber, tracketch hydrophilic polycarbonate, track-etch hydrophobic polycarbonate, track-etch polyimide, nanoporous anodic aluminum oxide, zeolite ZSM-5, and zeolite NaY. An analogy between the rate of pressure accumulation of the permeating gas behind the membrane and the charging of an electric capacitor in a single series RC circuit is proposed and thoroughly validated. The simultaneous permeation rates through different membranes demonstrated a very promising potential as characteristic fingerprints for 10 test gases, that is, helium, neon, argon, hydrogen, nitrogen, carbon dioxide, methane, ethane, propane, and ethylene, which are selected as representative examples of mono-, di-, tri-, and polyatomic gases and to include some homologous series as well as to allow testing the potential of the proposed system to discriminate between closely related gases such as ethane and ethylene or carbon dioxide and propane which have almost identical molecular masses. Finally, a preliminary investigation of the possibility of applying the developed gas permeation system for semiquantitative analysis of the CO 2 −N 2 binary mixture is also presented.

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“…In a recent study, Weller et al 88 provided an intercomparison between spontaneous Raman spectroscopy and CERS for simultaneous measurements of N 2 and O 2 in the ambient air. The authors also derived a comprehensive model to estimate the photon emission for both free space and cavity-based Raman signals and subsequently discussed the trade-offs in how to organize the cavity geometry for maximum gain in CERS.…”

mentioning

confidence: 99%

Cavity Ring-Down Spectroscopy: Recent Technological Advancements, Techniques, and Applications

2020

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Gas-phase Raman spectroscopy of non-reacting flows: comparison between free-space and cavity-based spontaneous Raman emission

Cited by 6 publications

References 53 publications

High-frequency measurement of concentration in an isothermal methane–air gas mixture using spontaneous Raman spectroscopy

High-frequency measurement of concentration in an isothermal methane–air gas mixture using spontaneous Raman spectroscopy

Gas Identification by Simultaneous Permeation through Parallel Membranes: Proof of Concept

Cavity Ring-Down Spectroscopy: Recent Technological Advancements, Techniques, and Applications

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