Hollow Cathode Discharges

Caroli, Sergio; Senofonte, Oreste

doi:10.1007/978-1-4899-2394-3_6

Cited by 13 publications

(10 citation statements)

References 131 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effect of He discharge gas pressure on the Fe(I) 385.9 nm emission was evaluated over the range 2−5 Torr. The observed response decreased about 25% across this range, typical for hollow cathode devices, wherein low pressures provide a more energetic excitation environment relative to higher pressures . Somewhat surprising is the fact that increases in pressure do not result in increased residence times of the analyte elements, as might be expected given the shorter mean-free paths.…”

Section: Resultsmentioning

confidence: 77%

“…Clearly seen are the results of enhanced collisional processes within the negative glow of the plasma as the current is increased from 30 to 60 mA. This is a more-or-less typical response for hollow cathode discharges, though the leveling of the responses above 60 mA indicates some form of limiting condition, either in the number of electrons or in the analyte mass . The effect of He discharge gas pressure on the Fe(I) 385.9 nm emission was evaluated over the range 2−5 Torr.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Sampling and Analysis of Particulate Matter by Glow Discharge Atomic Emission and Mass Spectrometries

et al. 1999

View full text Add to dashboard Cite

The direct introduction of particulate matter into glow discharge atomic emission and mass spectrometry sources through a particle beam/momentum separator apparatus is described. Vacuum action through a narrow (0.0625 in. i.d.) stainless steel tube allows the introduction of discrete samples of NIST SRM 1648 urban particulate matter (UPM) and caffeine in powder form. Introduction of "ambient" airborne particulate matter is also possible. Particles passing through the aerodynamic momentum separator impinge on the heated (∼200-250 °C) inner surface of the glow discharge plasma volume and are flash-vaporized. The resultant atoms/molecules are subjected to excitation/ionization collisions within the low-pressure (0.5-5 Torr of He or Ar) plasma, producing characteristic photon emission and/or signature ionic species. In this way, atomic emission and mass spectrometry identification of particle constituents is possible. Basic design aspects of the apparatus are presented, and demonstrations of atomic emission detection of the constituents in the NIST SRM illustrate the general characteristics of the approach. Transient atomic emission signals are captured for the introduction of preweighed, discrete samples, with the integrated areas used to construct analytical response curves. Limits of detection using this relatively simple atomic emission system are on the order of tens of nanograms for sample masses of ∼50 μg. Mass spectrometric monitoring of introduced caffeine particles and a mixture of polycyclic aromatic hydrocarbons (PAHs) illustrates the ability of the glow discharge plasma to produce high-quality, library (electron impact) searchable mass spectra of molecular species while also yielding isotopic identification of elemental components of the UPM. Limits of detection for Fe in the NIST SRM are on the order of 175 ng of material, equivalent to ∼7 ng of analyte Fe. It is believed that the small size, low power consumption, ease of operation, and multimode sampling capabilities (AES/MS) of the particle beam-glow discharge (PB-GD) apparatus hold promise for applications in continuous monitoring and discrete particle sampling.

show abstract

Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Sampling and Analysis of Particulate Matter by Glow Discharge Atomic Emission and Mass Spectrometries

et al. 1999

View full text Add to dashboard Cite

show abstract

“…The HCE has a complicated dependence on various discharge parameters and an extensive literature is devoted to it (e.g. [7][8][9][10][11][12]). Most properties of the HCE result from the more efficient use of the fast electrons and the ions compared to other discharge geometries.…”

Section: Introductionmentioning

confidence: 99%

“…This regime represents the high-voltage (low-current) phase of the HCD operation (feature (f) of the HCE) when the discharge is 'pulled' out of the hollow and runs outside it (e.g. [9,35]). This regime is also known as a regime with a (longitudinal) electron beam and is realized by reducing either the intercathode separation or the gas pressure [9].…”

Section: It Is Then Convenient To Introduce the Normalized Emcmentioning

confidence: 99%

See 1 more Smart Citation

On the hollow-cathode effect: conventional and modified geometry

Arslanbekov

Kudryavtsev

Tobin

1998

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

The hollow-cathode effect (HCE) is studied for conventional and modified hollow-cathode discharges (HCDs). HCDs are considered that operate at substantial current densities and moderate voltages (e.g. in a conventional HCD, >1 mA cm −2 and <400 V, respectively), which are typical of the HCDs in common use. A simple kinetic model is developed and used to predict that the HCE exists even if a small fraction of the total ionization occurs in the cathode-fall regions (CF). The HCE results from ionization becoming more efficient in the negative glow (NG) so that no significant ionization is required to occur in the CF. Consequently, the size of the CF diminishes and a large increase in current takes place. The main features of the HCE are reproduced and good agreement with experiment is found. The results suggest that low-slope-resistance voltage-current characteristics are realized when the ionization in the CF is small. It is next demonstrated that the ions play an important role and that even a small increase in the ion flux from the NG to the CF can contribute to the HCE. The principal geometrical criteria for the conventional and modified HCDs are presented. A segmented HCD tube is considered to study an interesting transition from a conventional HCD through a modified HCD to an abnormal glow discharge. Finally, the principal physical mechanisms which determine the operating characteristics of the modified HCD are identified and discussed.

show abstract

Sputtering—atomizing and optogalvanic properties of an Ar–Mg Hollow cathode discharge

Zhechev

Atanassova

1998

Vacuum

View full text Add to dashboard Cite

Hollow Cathode Discharges

Cited by 13 publications

References 131 publications

Sampling and Analysis of Particulate Matter by Glow Discharge Atomic Emission and Mass Spectrometries

Sampling and Analysis of Particulate Matter by Glow Discharge Atomic Emission and Mass Spectrometries

On the hollow-cathode effect: conventional and modified geometry

Sputtering—atomizing and optogalvanic properties of an Ar–Mg Hollow cathode discharge

Contact Info

Product

Resources

About