Metastable atom density in helium, neon, and argon glow discharges

Hardy, K.A.; Sheldon, J. W.

doi:10.1063/1.330489

Cited by 28 publications

(19 citation statements)

References 14 publications

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“…26 and 57͒ regimes, where the Ar m metastable population has been measured ͑by laser-induced fluorescence or by optical emission͒ and calculated ͑with a hybrid model͒ at similar conditions as under study here. Experimental and calculation studies performed in Ar PC discharges 28,29,53 at 0.075-4 Torr show that the metastable population increases up to 0.1 Torr and then decreases, i.e., the metastable population appears to saturate by the effect of pressure at much lower values. This results from the much larger vessel dimensions in these experiments, so that the diffusion rate is significantly reduced, and hence, the relative importance of volume-quenching mechanisms increases.…”

Section: Some Features Of the Measured Profiles Can Howevermentioning

confidence: 97%

“…Also some studies have been performed with respect to the role of metastables in the glow discharge with formation of a positive column ͑PC͒. 28,29 In the present paper, we will analyse the role of Ar m metastable atoms in a HCD, using a metastable transport model, which is combined with a hybrid Monte Carlo fluid model for electrons, Ar + and Cu + ions, fast Ar atoms ͑Ar f ͒, and fast and thermal Cu atoms. A similar combination of models has been applied in the literature for the simulation of glow discharges with planar cathode, both in Ar, in dc, 30 and rf ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

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Study of the Ar metastable atom population in a hollow cathode discharge by means of a hybrid model and spectrometric measurements

Baguer

Bogaerts

Gijbels

et al. 2005

Journal of Applied Physics

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The role of the metastable Ar atoms in a 1-cm-diameter cylindrical hollow cathode discharge ͑HCD͒ is studied self-consistently based on a hybrid model and experimental measurements in the pressure range of 0.3-1 Torr and currents of 1-10 mA. The model comprises submodels based on the principles of Monte Carlo and fluid simulations. The Monte Carlo model describes the movement of the fast electrons, fast Ar and Cu atoms, and fast Ar + and Cu + ions as particles, while in the fluid model, the slow electrons, Ar + , Cu + ions, Cu, and Ar metastable atoms are treated as a continuum. The population of the two metastable states within the 3p 5 4s configuration ͑ 3 P 2 and 3 P 0 ͒ were combined into one collective level, for which the continuity equation was written. Typical calculation results are, among others, the two-dimensional profiles of the production and the loss rates of Ar metastable atoms, as well as the metastable atom densities and fluxes throughout the complete HCD. Moreover, the calculated radial profiles ͑averaged over the axial direction͒ of the Ar metastable atom density are compared with experimental radial density profiles recorded by laser absorption spectroscopy. The relative importance of the different processes determining the Ar metastable population is analyzed, as well as the influence of pressure and voltage on them. Experimental results evidence the presence of the metastable atom production source at the cathode surface, probably originating from fast Ar + ions and Ar atoms impinging on it. Comparison between experimental and calculated Ar metastable atom densities shows a good agreement at low pressures, but at 1 Torr the calculated values differ by a factor of 2 from the measured ones. Several possible explanations for this discrepancy are discussed.

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Section: Some Features Of the Measured Profiles Can Howevermentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Study of the Ar metastable atom population in a hollow cathode discharge by means of a hybrid model and spectrometric measurements

Baguer

Bogaerts

Gijbels

et al. 2005

Journal of Applied Physics

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“…From (b) to (f) there is an eightfold increase in the 56Fe + intensity. bution) and destruction processes (collisions with fast electrons, neutral atoms, other metastable species, and the vessel wall) [14]. Secondary electron emission from the cathode replenishes electrons lost in the plasma collisions and maintains the average electron temperature.…”

Section: Pulse Patternsmentioning

confidence: 99%

The pulsed glow discharge as an elemental ion source

Klingler

Savickas

Harrison

1990

J. Am. Soc. Mass Spectrom.

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A pulsed glow discharge, rather than a conventional constant dc voltage discharge, is used as an ion source for a quadrupole mass spectrometer. Both sputter yield and ion signal are enhanced by using the pulsed system because of an increase in the voltage necessary to maintain a constant average current at the cathode over the pulse period. Irregularities are seen in the pulse spectrum that appear as rapid surges in the ion signal for both sputtered and contaminant gas species. These peaks appear at the beginning of the pulse for gaseous species but are limited to the postpulse period for sputtered species. Differences in the signal forms allow for the discrimination against selected types of ion signals by using narrow data collection gates placed over different portions of the pulse period.

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“…A comparison between experiment and calculated metastable densities was also carried out by Kubota et al [14] for He in a DC and RF glow discharge. Hardy and Sheldon [15] have studied He, Ne and Ar gases. Den Hartog et al [16,17] have studied He gas.…”

Section: Introductionmentioning

confidence: 99%

Investigations of argon and neon abnormal glow discharges in the presence of metastable atom density with fluid model

2016

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In this manuscript an investigation of a DC argon and neon abnormal glow discharges with metastable atom density is presented. The values of pressure lie between 133.32 and 330 Pa, and the voltage ranges from 250 to 400 V in the case of argon gas. In the case of neon gas, the pressure has a value of 399.92 Pa (3 Torr) and the voltage ranges from 300 to 500 V. In this framework, an analysis of abnormal glow discharge characteristics is carried out in the case of input data taken from the Boltzmann equation in the multi-term approximation, and in the case of input data obtained from BOLISG+ code. With these differences of input data in the same gas, the output results are different; it appears in the cathodic region. The spatio-temporal distributions of electron and ion densities, the potential and electric field, the mean electron energy and the metastable atom density are shown. A 1D fluid model is used to solve self-consistently the first three moments of the Boltzmann’s equation coupled with the Poisson’s equation. The role of the presence of metastable atom density in the fluid model is clearly because of the domination of ionization processes by both stepwise and penning ionizations. Our results are validated with those obtained by both recent paper and experimental results.

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Metastable atom density in helium, neon, and argon glow discharges

Cited by 28 publications

References 14 publications

Study of the Ar metastable atom population in a hollow cathode discharge by means of a hybrid model and spectrometric measurements

Study of the Ar metastable atom population in a hollow cathode discharge by means of a hybrid model and spectrometric measurements

The pulsed glow discharge as an elemental ion source

Investigations of argon and neon abnormal glow discharges in the presence of metastable atom density with fluid model

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