Modeling positive ion current to a planar probe in low-pressure electronegative discharges

2009 ◽  
Vol 16 (6) ◽  
pp. 063503 ◽  
Author(s):  
T. H. Chung
Keyword(s):  
Low Pressure ◽  
Ion Current ◽  
Positive Ion

scholarly journals Influence of the Ion Mass in the Radial to Orbital Transition in Weakly Collisional Low-Pressure Plasmas Using Cylindrical Langmuir Probes

2020 ◽  
Vol 10 (17) ◽  
pp. 5727 ◽  
Author(s):  
Guillermo Fernando Regodón ◽  
Juan Manuel Díaz-Cabrera ◽  
José Ignacio Fernández Palop ◽  
Jerónimo Ballesteros
Keyword(s):  
Free Path ◽  
Debye Length ◽  
Mean Free Path ◽  
Low Pressure ◽  
Plasma Potential ◽  
Ion Current ◽  
Ion Temperature ◽  
Langmuir Probes ◽  
The Relationship ◽  
Positive Ion

This paper presents an experimentally observed transition from the validity of the radial theories to the validity of the orbital theories that model the ion current collected by a cylindrical Langmuir probe immersed in low-pressure, low-temperature helium plasma when it is negatively biased with respect to the plasma potential, as a function of the positive ion-neutral collision mean free path to the Debye length ratio Λ=λ+/λD. The study has been also conducted on argon and neon plasmas, which allows a comparison based on the mass of the ions, although no transition has been observed for these gases. As the radial or orbital behavior of the ions is essential to establish the validity of the different sheath theories, a theoretical analysis of such a transition not only as a function of the parameters Λ and β=T+/Te, T+ and Te being the positive ion and electron temperature, respectively, but also as a function of the ion mass is provided. This study allows us to recognize the importance of the mass of the ion as the parameter that explains the transition in helium plasmas. Motivated by these theoretical arguments, a novel set of measurements has been performed to study the relationship between the Λ and β parameters in the transition that demonstrate that the effect of the ion mean free path cannot be completely ignored and also that its influence on the ion current collected by the probe is less important than the effect of the ion temperature.

rf modulation of positive‐ion energies in low‐pressure discharges

1990 ◽  
Vol 68 (11) ◽  
pp. 5519-5527 ◽  
Author(s):  
S. G. Ingram ◽  
N. St. J. Braithwaite
Keyword(s):  
Low Pressure ◽  
Ion Energies ◽  
Positive Ion

Ammonia in the Ion-Source. III. Clustering With N-Oxides, Sulfoxides and Sulfones

1986 ◽  
Vol 39 (12) ◽  
pp. 2161 ◽  
Author(s):  
RG Gillis
Keyword(s):  
Chemical Ionization ◽  
Low Pressure ◽  
Ion Source ◽  
Unimolecular Decomposition ◽  
Positive Ion

Under positive ion chemical ionization conditions, with ammonia as reagent gas at relatively low pressure, N-oxides, sulfoxides and sulfones form clusters with a proton and one or more ammonia molecules; these clusters can be represented as [M+H]+, [M+NH4]+, [M+N2H7]+, [2M+H]+ and [2M+NH4]+. The unimolecular decomposition of the clusters can be followed by the accompanying metastable peaks.

Space Potential and Ion Energies in a Low Pressure Discharge Containing at least Two Negative Species

1988 ◽  
Vol 117 ◽  
Author(s):  
S G Ingram ◽  
N St J Braithwaite
Keyword(s):  
Energy Distribution ◽  
Collisionless Plasma ◽  
Negative Ions ◽  
Potential Drop ◽  
Low Pressure ◽  
Type Model ◽  
Plasma Parameters ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
Positive Ion

AbstractA Tonks-Langmuir type model for a one-dimensional low pressure (collisionless) plasma containing at least two species of Maxwellian negative charge carriers is examined. The solutions of this model yield the positive ion energy distribution at the sheath edge without needing to specify the ionization process. This distribution has a width consistent with the potential drop across the plasma, and is shown to satisfy the generalised Bohm criterion for sheath formation. However by assuming a form for the ionization rate in the plasma, the potential profile across the discharge has been calculated. It has been found that for a range of plasma parameters the solution for the potential at which quasineutrality fails becomes triple valued; the physical solution in this regime is identified.Many plasmas used for materials processing contain negative ions. It is important to understand how these ions influence the positive ion energy distribution at the substrate where the processing occurs.This work is also of relevance to the behaviour of Langmuir probes in electronegative plasmas.

scholarly journals Floating Multiple Probe Systems for Plasma Measurements

1962 ◽  
Vol 15 (2) ◽  
pp. 162 ◽  
Author(s):  
KM Burrows
Keyword(s):  
Electron Temperature ◽  
Voltage Characteristic ◽  
Ion Current ◽  
Current Voltage Characteristic ◽  
Ion Movement ◽  
Current Voltage ◽  
Probe System ◽  
Multiple Probe ◽  
Plasma Measurements ◽  
Positive Ion

A new analysis of the current voltage characteristic of a floating double probe system is given, showing that the electron temperature must be estimated from measurements at the point of inflection of the characteristic if positive ion movement contributes to the probe circuit current. Temperature measurements will still be in error if the rates of variation of positive ion current to the two probes are not closely similar as the potential difference between them is varied. An alternative experimental technique is described which will yield correct temperature estimates in such circumstances, and is simpler and less perturbing to the plasma than the floating triple probe method.

The Positive Ion Current at the Cathode in the Glow Discharge

1932 ◽  
Vol 42 (6) ◽  
pp. 786-794 ◽  
Author(s):  
A. Keith Brewer ◽  
R. R. Miller
Keyword(s):  
Glow Discharge ◽  
Ion Current ◽  
Positive Ion

scholarly journals Impact of the positive ion current on large size neutrino detectors and delayed photon emission

2018 ◽  
Vol 13 (04) ◽  
pp. C04015-C04015 ◽  
Author(s):  
R. Santorelli ◽  
S. di Luise ◽  
E. Sanchez Garcia ◽  
P. Garcia Abia ◽  
T. Lux ◽  
...  
Keyword(s):  
Photon Emission ◽  
Ion Current ◽  
Neutrino Detectors ◽  
Large Size ◽  
Positive Ion
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