Gas temperature in the cathode region of a dc glow discharge with a thermionic cathode

Winter, J.; Lange, Hartmut; Golubovskiǐ, Yu. B.

doi:10.1088/0022-3727/41/8/085210

Cited by 8 publications

(4 citation statements)

References 20 publications

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“…Higher gas temperatures were observed in the region close to the electrode surface. This was consistent with earlier studies on the DC glow discharge, which show that the gas temperature is higher at the cathode surface and decreases with the distance away from the cathode. − This was attributed to the increasing collisions between gas molecules and electrons emitted from the cathode surface. In our rf-GD system, the two electrodes alternated between cathode and anode, leading to a higher temperature in the region close to both electrodes.…”

Section: Resultssupporting

confidence: 92%

Rapid Elemental Analysis of Aerosols Using Atmospheric Glow Discharge Optical Emission Spectroscopy

Zheng

Kulkarni

2017

Anal. Chem.

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A new, low-cost approach based on the application of atmospheric radio frequency glow discharge (rf-GD) optical emission spectroscopy (OES) has been developed for near real-time measurement of multielemental concentration in airborne particulate matter. This method involves deposition of aerosol particles on the tip of a grounded electrode of a coaxial microelectrode system, followed by ablation, atomization and excitation of the particulate matter using the rf-GD. The resulting atomic emissions were recorded using a spectrometer for elemental identification and quantification. The glow discharge plasma was characterized by measuring spatially resolved gas temperatures (378 – 1438 K) and electron densities (2 – 5 × 1014 cm−3). Spatial analysis of the spectral features showed that the excitation of the analyte occurred in the region near the collection electrode. The temporal analysis of spectral features in the rf-GD showed that the collected particles were continuously ablated; the time for complete ablation of 193 ng of sucrose particles was found to be approximately 2 s. The system was calibrated using 100 nm particles containing C, Cd, Mn, and Na, respectively. Our method provides limits of detection in the range of 0.055 – 1.0 ng, and a measurement reproducibility of 5 – 28%. This study demonstrates that the rf-GD can be an excellent excitation source for the development of low-cost hand-held sensors for elemental measurement of aerosols.

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Section: Resultssupporting

confidence: 92%

Rapid Elemental Analysis of Aerosols Using Atmospheric Glow Discharge Optical Emission Spectroscopy

Zheng

Kulkarni

2017

Anal. Chem.

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“…This is also due to the bombardment of the cathode surface by ions launched from the plasma and accelerated in the strong electric field in the cathode fall and by fast neutral molecules created in collisions with ions in the cathode fall. The cathode temperature has a significant influence on the properties of the cathode fall [26][27][28][29][30][31] and on the cathode vaporization rate. In addition, the vaporization rate and the gas temperature determine the saturation state of the vapour in the gas which in turn determines the concentration and size of the primary particles.…”

Section: Discussionmentioning

confidence: 99%

Influence of the inter-electrode distance on the production of nanoparticles by means of atmospheric pressure inert gas dc glow discharge

Hontañón

Palomares

Guo

et al. 2014

J. Phys. D: Appl. Phys.

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Hontanõn, E.; Palomares Linares, J.M.; Guo, C.; Engeln, R.A.H.; Nirschi, H.; Kruis, F. Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication Citation for published version (APA):Hontanõn, E., Palomares Linares, J. M., Guo, C., Engeln, R. A. H., Nirschi, H., & Kruis, F. (2014). Influence of the interelectrode distance on the production of nanoparticles by means of atmospheric pressure inert gas DC glow discharge. Journal of Physics D: Applied Physics, 47, 415201-1/12. DOI: 10.1088/0022-3727/47/41/415201 General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractThis work is aimed at investigating the influence of the inter-electrode spacing on the production rate and size of nanoparticles generated by evaporating a cathode on an atmospheric pressure dc glow discharge. Experiments are conducted in the configuration of two vertically aligned cylindrical electrodes in upward coaxial flow with copper as a consumable cathode and nitrogen as a carrier gas. A constant current of 0.5 A is delivered to the electrodes and the inter-electrode distance spanned from 0.5 to 10 mm. Continuous stable nanoparticle production is attained by optimal coaxial flow convection cooling of the cathode. Both the particle production rate and the primary particle size increase with the inter-electrode spacing up to nearly 5 mm and strongly decrease with an increasing inter-electrode distance beyond 5 mm. Production rates in the range of 1 mg h −1 of very small nanoparticles (<10 nm) are attained by a micro glow discharge (<1 mm); while glow discharges of intermediate sizes (<5 mm) result in production rates ...

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“…From the Doppler broadening of the hyperfine components contributing to this line profile, the temperature is deduced. Furthermore, the dependence of the temperature on the distance z from the cathode is corrected by a formalism described in detail in [6]. In an additional experiment, where the laser wavelength is held at a constant value λ 0 , the 2-D optical depth τ (r, z) of the whole spot region is ascertained [7].…”

Section: Jörn Winter and Hartmut Langementioning

confidence: 99%

“…1(c), the isotherms of the gas temperature obtained in the spot vicinity are shown. Here, the radial temperature inhomogeneity is taken into account according to [6], yielding the corrected temperature profile T c . Due to the hot cathode spot, the corrected gas temperature profile is maximal directly in front of the cathode (T c > 600 K) and decreases to room temperature for distances z > 6 mm.…”

Section: Jörn Winter and Hartmut Langementioning

confidence: 99%

Spot Mode Operation of a Low-Pressure Helium–Xenon Glow Discharge

Winter

Lange

2011

IEEE Trans. Plasma Sci.

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The cathode region (CR) of a low-pressure He-Xe discharge with a flat thermionic emitting cathode in spot mode has been experimentally investigated by means of tunable diode laser absorption spectroscopy. Due to the strong inhomogeneity of the spot plasma, a multidimensional consideration of the CR is necessary to obtain correct results. This was achieved by an experimental setup, which provides a space-resolved measurement of the absorption signal. Furthermore, the plasma inhomogeneity was considered in the subsequent analysis of the obtained data too. The gas temperature in the surrounding volume was determined. Furthermore, the spatial density profile of the xenon 6s[3/2] 2 metastable atoms was measured in the vicinity of the spot.Index Terms-Atom number density, gas temperature, helium, LAAS, mercury-free low pressure discharge lamp, spot mode, xenon.L OW-PRESSURE glow discharges in He-Xe mixtures can be used for lighting purposes in mercury-free fluorescent lamps [1]. During the last years, investigations have been accomplished on their output characteristics and efficiency in dependence on parameters such as mixture composition, pressure, discharge current, and operation mode [2]. However, the lifetime of this type of fluorescent lamps is too low and will mainly be limited by the performance of the electrodes and their interaction with the surrounding plasma. Therefore, the physical processes in the cathode region (CR) play an important role in mercury-free fluorescent lamps on the basis of xenon low-pressure glow discharges. The extensive literature that exists on this subject is concerned with theoretical and experimental studies on the CR in low-pressure gas discharge lamps with mercury as carrier gas [3] and on Grimm-type glow discharges in argon [4] and helium [5]. Only a limited number of investigations studied hot cathode glow discharges and, particularly, the gas temperature and the atom number density in the vicinity of the cathode.In this paper, measurements of the spatial gas temperature and the optical depth of the 823.16-nm Xe transition, which is correlated to the atom number densities of the lowest excited metastable Xe state in the vicinity of a cathode with a hot spot, are presented. Both are yielded using diode laser absorption technique.The line profile of the Xe-transition 6p[3/2] 2 −6s[3/2] 2 at the center wavelength of 823.16 nm, respectively, was as-

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Gas temperature in the cathode region of a dc glow discharge with a thermionic cathode

Cited by 8 publications

References 20 publications

Rapid Elemental Analysis of Aerosols Using Atmospheric Glow Discharge Optical Emission Spectroscopy

Rapid Elemental Analysis of Aerosols Using Atmospheric Glow Discharge Optical Emission Spectroscopy

Influence of the inter-electrode distance on the production of nanoparticles by means of atmospheric pressure inert gas dc glow discharge

Spot Mode Operation of a Low-Pressure Helium–Xenon Glow Discharge

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