Pressure broadening and pressure shift of the 410 nm indium line perturbed by foreign gases

Eberz, J.; Huber, G.; Kühl, T.; Ulm, G.

doi:10.1088/0022-3700/17/15/020

Cited by 6 publications

(4 citation statements)

References 13 publications

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“…Relative hyperfine peak separations [11] and intensities [12] were specified in the fit. The pressure broadening coefficient is in good agreement with that expected for N 2 dominated collisional broadening at this temperature and pressure [13]. Note that the total width of the 5 2 P 1/2 →6 2 S 1/2 transition is observed to be around 1 cm -1 (30 GHz), which is considerably wider than what has previously been assumed (2 GHz) and used in TLAF measurements [8].…”

Section: Resultssupporting

confidence: 87%

Diode laser induced fluorescence spectroscopy for combustion thermometry

Burns

Hult

Kaminski³

2005

J. Phys.: Conf. Ser.

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This paper describes the first use of novel blue diode lasers to make temperature measurements based on fluorescence. As a demonstration of this principle, indium atoms were seeded as a probe species into flames and the resulting diode laser induced fluorescence allowed an accurate determination of the temperature at a point. This permits spatially resolved measurements to be made, which are impossible to achieve using the established absorption based sensors. The technique opens up a range of application possibilities in dynamic and inhomogeneous reacting flows.

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Section: Resultssupporting

confidence: 87%

Diode laser induced fluorescence spectroscopy for combustion thermometry

Burns

Hult

Kaminski³

2005

J. Phys.: Conf. Ser.

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“…The pressure shift of the 5 2 P 1/2 → 6 2 S 1/2 line of indium with nitrogen is reported by Eberz et al [34] and even if there are other species present in the flue gas of the burner nitrogen is the major collision partner and can thus be used to estimate the shift. There is no data reported for the three remaining lines but as gallium is homologous to indium one can assume the pressure shift of the lines is in the same order.…”

Section: Burner Measurementsmentioning

confidence: 59%

Diode laser-based thermometry using two-line atomic fluorescence of indium and gallium

et al. 2017

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the requirements listed above, is two-line atomic fluorescence (TLAF) [4][5][6]. TLAF is a laser-based ratiometric technique, in which the temperature-dependent population of two lower lying electronic states, of a seeded atom, is probed by laser excitation and the ratio of the resulting fluorescence is correlated with the temperature of the gas. TLAF offers several beneficial features for temperature measurements in reactive flows. Firstly, no a priori knowledge of the combustion environment is necessary as the technique is independent of quenching due to the excitation to a common upper state [7]. Secondly, the use of an atomic species as temperature marker offers advantages such as providing high transition probabilities yielding strong fluorescence signals as well as being free from errors related to vibrational and rotational energy transfer existing in molecules [8,9]. Thirdly, TLAF also has the possibility for thermometry measurements in sooting and particulate-laden flames as the detection wavelength can be shifted from the excitation wavelength [10,11]. The disadvantage of TLAF is that an atomic species, not normally present in the flame, has to be introduced which may add complexities to the experimental set-up.Two-line atomic fluorescence has been developed in steps where the first theoretical ground work was conducted by Alkemade [7] and experimentally demonstrated shortly thereafter using atomic lamps [12,13]. With the advent of suitable lasers, TLAF became a tool for temperature measurements with imaging capabilities in non-steady environments [4,10,11,[14][15][16]. Recently, TLAF measurement has been extended from the linear regime to non-linear regime by Medwell et al. [4] and to the saturation regime by Manteghi et al. [14] in an attempt to maximize the fluorescence signal for instantaneous temperature measurements. With the improvement in regards to available power and wavelengths of diode lasers, TLAF measurements using diode lasers have been shown to give accurate temperatures in both low-pressure and atmospheric Abstract A robust and relatively compact calibration-free thermometric technique using diode lasers two-line atomic fluorescence (TLAF) for reactive flows at atmospheric pressures is investigated. TLAF temperature measurements were conducted using indium and, for the first time, gallium atoms as temperature markers. The temperature was measured in a multi-jet burner running methane/air flames providing variable temperatures ranging from 1600 to 2000 K. Indium and gallium were found to provide a similar accuracy of ~ 2.7% and precision of ~ 1% over the measured temperature range. The reliability of the TLAF thermometry was further tested by performing simultaneous rotational CARS measurements in the same experiments.

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“…16 The larger observed pressure broadening compared with the estimated broadening could be due to three different factors: A temperature T at the measurement location that is lower than 1500 K would lead to a correspondingly larger pressure broadening Dn because Dn ϳ T 2h (h is the temperature exponent for collision broadening), slightly higher broadening coeff icients for species other than N 2 compared with the coeff icient for N 2 would also lead to a larger observed broadening, and a value of h lower than the 0.7 predicted by the impact approximation would lead to a larger value of the estimated broadening. 15 The strong signals obtained demonstrate a clear potential for f luorescence-based temperature measurements by use of indium-based two-line atomic f luorescence (TLAF). 4,17 This would, for the f irst time to our knowledge, allow the use of diode lasers for spatially precise temperature measurements, avoiding averaging effects normally associated with absorption-based temperature techniques.…”

mentioning

confidence: 94%

“…As a comparison, the expected pressure broadening of indium in a pure N 2 gas, which is the most abundant species in the f lame, at a temperature of 1500 K is 6.3 GHz. This estimate is based on indium line-broadening rates reported by Eberz et al 15 and uses the impact pressure-broadening approximation. 16 The larger observed pressure broadening compared with the estimated broadening could be due to three different factors: A temperature T at the measurement location that is lower than 1500 K would lead to a correspondingly larger pressure broadening Dn because Dn ϳ T 2h (h is the temperature exponent for collision broadening), slightly higher broadening coeff icients for species other than N 2 compared with the coeff icient for N 2 would also lead to a larger observed broadening, and a value of h lower than the 0.7 predicted by the impact approximation would lead to a larger value of the estimated broadening.…”

mentioning

confidence: 99%

Measurements of the indium hyperfine structure in an atmospheric-pressure flame by use of diode-laser-induced fluorescence

2004

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We report on what we believe is the first demonstration of laser-induced fluorescence (LIF) in flames by use of diode lasers. Indium atoms seeded into an atmospheric-pressure flame at trace concentrations are excited by a blue GaN laser operating near 410 nm. The laser is mounted in an external-cavity configuration, and the hyperfine spectrum of the 5(2)P1/2 --> 6(2)S1/2 transition is captured at high resolution in single-wavelength sweeps lasting less than one tenth of a second. The research demonstrates the potential of diode-based LIF for practical diagnostics of high-temperature reactive flows.

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Pressure broadening and pressure shift of the 410 nm indium line perturbed by foreign gases

Cited by 6 publications

References 13 publications

Diode laser induced fluorescence spectroscopy for combustion thermometry

Diode laser induced fluorescence spectroscopy for combustion thermometry

Diode laser-based thermometry using two-line atomic fluorescence of indium and gallium

Measurements of the indium hyperfine structure in an atmospheric-pressure flame by use of diode-laser-induced fluorescence

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