A study of excitation mechanisms in atmospheric microwave induced argon plasmas

Timmermans, E.A.H.; Thomas, Ingo; Jonkers, J Jeroen; Mullen, van der Jjam Joost

doi:10.1007/978-94-017-0633-9_54

Cited by 10 publications

(14 citation statements)

References 3 publications

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“…On the other hand, the atomic lines decay more slowly than expected from equation (12). Moreover, the more highly excited state of the two decays the slower, which is a further contradiction.…”

Section: Atomic Line Responsementioning

confidence: 77%

“…In an effort to understand the influence of such cooling on emission, it is useful to review the results of previous power interruption experiments. These have been chiefly performed on atmospheric argon plasmas in open flowing ICP or microwave torches [11,12]. The interruption of such experiments was facilitated by distinguishing two typical reactions: the so-called Boltzmann and Saha responses.…”

Section: Non-lte Responsesmentioning

confidence: 99%

“…Fey [11] established a link between the delayed response of spectral lines to convection and thus determined the velocity field in an ICP. Timmermans [12] used the technique to study the influence of the heavy particle temperature on line emission from metals in microwave torches. De Regt [13] and van de Sande [14] investigated the behaviour of the electron gas with the help of Thomson scattering during the power interruption.…”

Section: Introductionmentioning

confidence: 99%

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Measured and simulated response of a high pressure sulfur spectrum to power interruption

Johnston¹,

Mullen²

2004

J. Phys. D: Appl. Phys.

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The power supplied to a high pressure, microwave sulfur plasma sustained by microwaves is interrupted on short timescales. The response of the molecular spectrum between 400 and 900 nm is measured during this interruption. Characteristic decay times of around 20 ms are found and are due chiefly to the large heat capacity of the reacting mixture. The results of a time dependent local thermal equilibrium model of the interruption, including radiation transport of the entire molecular spectrum and heat conduction, are also presented. The simulated signal decay agrees with experiment not only in magnitude but also as a function of wavelength.

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Section: Atomic Line Responsementioning

confidence: 77%

Section: Non-lte Responsesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Measured and simulated response of a high pressure sulfur spectrum to power interruption

Johnston¹,

Mullen²

2004

J. Phys. D: Appl. Phys.

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“…For the selection of the gas temperature we follow [30] where T g was determined by means of Rayleigh scattering. A whole field of T g values was found ranging from 800 to 4500 K. A remarkable finding is that in the active plasma zone, the region where the electrons are, the gas temperature is low and on the order of 900 K. Another study [31] reports higher T g values by equating the gas temperature to the rotational or vibrational temperature of the molecules. However, most likely these molecules are not located in but are at the periphery of the active plasma zone.…”

Section: Plasma Conditionsmentioning

confidence: 93%

A novel method to determine the electron temperature and density from the absolute intensity of line and continuum emission: application to atmospheric microwave induced Ar plasmas

Iordanova

Palomares

Gamero

et al. 2009

J. Phys. D: Appl. Phys.

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An absolute intensity measurement (AIM) technique is presented that combines the absolute measurements of the line and the continuum emitted by strongly ionizing argon plasmas. AIM is an iterative combination of the absolute line intensity–collisional radiative model (ALI–CRM) and the absolute continuum intensity (ACI) method. The basis of ALI–CRM is that the excitation temperature T13 determined by the method of ALI is transformed into the electron temperature Te using a CRM. This gives Te as a weak function of electron density ne. The ACI method is based on the absolute value of the continuum radiation and determines the electron density in a way that depends on Te. The iterative combination gives ne and Te. As a case study the AIM method is applied to plasmas created by torche à injection axiale (TIA) at atmospheric pressure and fixed frequency at 2.45 GHz. The standard operating settings are a gas flow of 1 slm and a power of 800 W; the measurements have been performed at a position of 1 mm above the nozzle. With AIM we found an electron temperature of 1.2 eV and electron density values around 1021 m−3. There is not much dependence of these values on the plasma control parameters (power and gas flow). From the error analysis we can conclude that the determination of Te is within 7% and thus rather accurate but comparison with other studies shows strong deviations. The ne determination comes with an error of 40% but is in reasonable agreement with other experimental results.

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“…In general, MPT possesses high excitation efficiency, because the excitation temperature of the plasma is relatively high, about 800–2000 K [ 31 ], depending on the microwave power and the working gas. But the ionization degree of MPT is only 0.01%, far less than that of ICP, 0.2% [ 32 ]. Thereby some groups with bright characterization can be as reagent ions and make the mass spectra easy assignment.…”

Section: Resultsmentioning

confidence: 99%

Some Rare Earth Elements Analysis by Microwave Plasma Torch Coupled with the Linear Ion Trap Mass Spectrometry

Xiong

Jiang

et al. 2015

International Journal of Analytical Chemistry

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A sensitive mass spectrometric analysis method based on the microwave plasma technique is developed for the fast detection of trace rare earth elements (REEs) in aqueous solution. The plasma was produced from a microwave plasma torch (MPT) under atmospheric pressure and was used as ambient ion source of a linear ion trap mass spectrometer (LTQ). Water samples were directly pneumatically nebulized to flow into the plasma through the central tube of MPT. For some REEs, the generated composite ions were detected in both positive and negative ion modes and further characterized in tandem mass spectrometry. Under the optimized conditions, the limit of detection (LOD) was at the level 0.1 ng/mL using MS2 procedure in negative mode. A single REE analysis can be completed within 2~3 minutes with the relative standard deviation ranging between 2.4% and 21.2% (six repeated measurements) for the 5 experimental runs. Moreover, the recovery rates of these REEs are between the range of 97.6%–122.1%. Two real samples have also been analyzed, including well and orange juice. These experimental data demonstrated that this method is a useful tool for the field analysis of REEs in water and can be used as an alternative supplement of ICP-MS.

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A study of excitation mechanisms in atmospheric microwave induced argon plasmas

Cited by 10 publications

References 3 publications

Measured and simulated response of a high pressure sulfur spectrum to power interruption

Measured and simulated response of a high pressure sulfur spectrum to power interruption

A novel method to determine the electron temperature and density from the absolute intensity of line and continuum emission: application to atmospheric microwave induced Ar plasmas

Some Rare Earth Elements Analysis by Microwave Plasma Torch Coupled with the Linear Ion Trap Mass Spectrometry

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