Self-absorption quantification in the case of SF6–N2 thermal plasma mixture

Habib, A.A.M.

doi:10.1016/j.jqsrt.2012.06.014

Cited by 8 publications

(6 citation statements)

References 48 publications

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“…For quantitative analysis, the authors used the escape factor to enhance the linearity of calibration curves by simply multiplying the measured sodium line [84]. Habib et al [85] employed the escape factor to predict the selfabsorption degrees of the low-level metastable states of atomic nitrogen in SF 6 -N 2 mixture and pure nitrogen plasmas. The relationship between the resonance escape factors of continuum as well as radiative nitrogen emission lines was drawn graphically.…”

Section: Escape Factormentioning

confidence: 99%

Mechanisms and efficient elimination approaches of self-absorption in LIBS

Hou

Zhang

2019

Plasma Sci. Technol.

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Laser-induced breakdown spectroscopy (LIBS) is a promising analytical spectroscopy technology based on spectroscopic analysis of the radiation emitted by laser-produced plasma. However, for quantitative analysis by LIBS, the so-called self-absorption effects on the spectral lines, which affect plasma characteristics, emission line shapes, calibration curves, etc, can no longer be neglected. Hence, understanding and determining the self-absorption effects are of utmost importance to LIBS research. The purpose of this review is to provide a global overview of self-absorption in LIBS on the issues of experimental observations and adverse effects, physical mechanisms, correction or elimination approaches, and utilizations in the past century. We believe that better understanding and effective solving the self-absorption effect will further enhance the development and maturity of LIBS.

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Section: Escape Factormentioning

confidence: 99%

Mechanisms and efficient elimination approaches of self-absorption in LIBS

Hou

Zhang

2019

Plasma Sci. Technol.

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“…Therefore, a one-dimensional calculation of radiative transport along the line of sight is conducted. For this, the spectral line shape in the plasma at every location along the line of sight is required [71]. Several line-broadening mechanisms are considered.…”

Section: Branching Ratio Analysismentioning

confidence: 99%

Characterization of a Reentry Plasma Wind-Tunnel Flow with Vacuum-Ultraviolet to Near-Infrared Spectroscopy

Hermann

Löhle

Zander

et al. 2016

Journal of Thermophysics and Heat Transfer

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This paper presents the analysis of optical emission spectroscopic measurements from vacuum ultraviolet (120 nm) to near infrared (960 nm) in a high-enthalpy air plasma flow corresponding to superorbital reentry conditions. The vacuum ultraviolet measurements have been realized with a new experimental setup allowing measurements through a bore hole in the sample. Using the commonly applied optical emission spectroscopy from the side, the radiation transport along the line of sight of the vacuum ultraviolet measurements has been assessed. This allowed the determination of the local ground state densities of atomic oxygen and atomic nitrogen from a branching ratio analysis and the blackbody limiting correction of the vacuum ultraviolet radiation. Through the analysis of the absorption in the borehole, the spectra have been corrected, resulting in a stagnation point radiative heat flux in the vacuum ultraviolet of 235 kW∕m 2 .= local mass-specific enthalpy, MJ∕kg I = arc current, A K = proportionality constant for air, W∕MJ∕kg·Pa 0.5 ·m 1.5 k = Boltzmann constant, J∕K k cal = calibration factor, W∕m 2 · nm · sr∕counts∕s L λ = spectral radiance, W∕m 2 · nm · sr L λ;Limit = blackbody limit spectral radiance, W∕m 2 · nm · sr M = magnification _ m = mass flow, g∕s n = number density, m −3 n i = excited state population density, m −3 n 0 = ground state population density, m −3 P = electric power, kW P k = spectral line shape, nm −1 p = pressure, hPa _ q = heat flux, kW∕m 2 R eff = effective nose radius, mm r = radial distance, mm S = raw signal, counts/s s = distance from the probe surface, mm s 0 = distance between object and focusing element, mm= vibrational quantum number x = axial distance from the nozzle, mm y = horizontal distance from the nozzle, mm z = vertical distance from the nozzle, mm α λ = absorption coefficient, m −1 δ = full width at half-maximum of line broadening, nm ε λ = emission coefficient, W∕m 3 · nm · sr ε = spectrally integrated emission coefficient, W∕m 3 · sr λ = wavelength, nm σ λ = absorption cross section, m 2 Subscripts BB = blackbody DL = deuterium lamp exc = electronic excitation IS = integrating sphere l = lower state rot = rotational tot = total trans = translational u = upper state vib = vibrational

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“…On the other hand, the values Ψ uℓ = Ψ j = 0 imply that the plasma is optically thin, or that no photoexcitation and photo-ionization can take place. The basic procedure of the calculation of the escape factors for both bound-bound transitions and free-bound transitions of photo-ionization processes have been described in details in a recent paper [28].…”

Section: The Mean Probability Of Photon Capturementioning

confidence: 99%

“…Hannachi et al [27] applied the escape factor method in order to study the effect selfabsorption on measured intensity in the laser-induced plasma. Recently, Habib [28] has developed the escape factor method to estimate quantitatively the self-absorption effect for the emission radiation from nitrogen in the case of SF 6 -N 2 thermal plasma mixture.…”

Section: Introductionmentioning

confidence: 99%

“…The main aim of this paper is to apply the theoretical procedures described in our previous paper [28] in the case of several nitrogen transitions and to present a quantitative estimation of the self-absorption phenomena for some fluorine resonance lines emitted by SF 6 -N 2 thermal plasma mixture with diameter 2 mm. The quantification of self-absorption can be treated parametrically by calculating the mean probability of photon capture for the resonance lines under investigation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Self-absorption quantification in the case of SF6–N2 thermal plasma mixture

Cited by 8 publications

References 48 publications

Mechanisms and efficient elimination approaches of self-absorption in LIBS

Mechanisms and efficient elimination approaches of self-absorption in LIBS

Characterization of a Reentry Plasma Wind-Tunnel Flow with Vacuum-Ultraviolet to Near-Infrared Spectroscopy

Calculation of the mean probability of photon capture for vacuum UV line emission of fluorine in the case of a thermal plasma mixture

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