Identification of plasma‐sheath resonances in a parallel‐plate plasma reactor

1995 ◽  
Vol 77 (10) ◽  
pp. 5455-5457 ◽  
Author(s):  
B. M. Annaratone ◽  
V. P. T. Ku ◽  
J. E. Allen
Keyword(s):  
Parallel Plate ◽  
Plasma Reactor ◽  
Plasma Sheath

scholarly journals Increasing the Surface Energy and Sterilization of Nonwoven Fabrics by Exposure to a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP)*

2001 ◽  
Vol os-10 (3) ◽  
pp. 1558925001OS-01 ◽  
Author(s):  
J. Reece Roth ◽  
Zhiyu Chen ◽  
Daniel M. Sherman ◽  
Fuat Karakaya ◽  
Peter P.-Y. Tsai ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Surface Energy ◽  
Parallel Plate ◽  
Discharge Plasma ◽  
Plasma Reactor ◽  
Active Species ◽  
Glow Discharge Plasma ◽  
Commercial Application ◽  
Nonwoven Fabrics ◽  
Normal Glow Discharge

A technique for generating active species with the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been developed and used to sterilize and increase the surface energy, wettability and wickability of nonwoven fabrics. The OAUGDP is a non-thermal, fourth-state-of-matter plasma with the classical characteristics of a low pressure DC normal glow discharge that operates in air (and other gases) at atmospheric pressure. No vacuum system or batch processing is necessary, and a wide range of applications to fabrics and polymeric webs can be accommodated in a parallel plate plasma reactor. In addition to directly exposing webs and workpieces to active species for surface energy increase in a parallel-plate reactor, we have shown that active species capable of sterilization can be convected at near room temperature to a remote exposure chamber. This technology is simple, produces many effects that can be obtained in no other way, generates minimal pollutants or unwanted byproducts, and is suitable for online treatment of webs, films, and fabrics. Early exposures of nonwoven fabrics to the OAUGDP required minutes to produce relatively small increases of surface energy. These durations appeared too long for commercial application to fast-moving webs. Recent improvements in OAUGDP power density, plasma quality and impedance matching of the power supply to the parallel plate plasma reactor have made it possible to raise the surface energy of a variety of polymeric webs (PP, PET, PE, etc.) to levels in the range of 60 to 70 dynes/cm with one second of exposure. In most cases these high surface energies were not durable, and fell off to 50 dynes/cm after periods of weeks to months. Here, we report the exposure of nonwoven fabrics made of PP and PET at the UTK Textiles and Nonwovens Development Center (TANDEC) to an impedance matched parallel plate OAUGDP for durations ranging from one second to several tens of seconds. Data will be reported on the surface energy, wettability and wickability as functions of time of exposure, and of the aging effect after exposure. We will report the use of a OAUGDP with air as the working gas to sterilize a broad range of microorganisms on a variety of surfaces, and in several distinct applications. These include a Remote Exposure Reactor to sterilize large workpieces 20 centimeters or more from the plasma-generating region, and a sterilizable air filter.

Concentration Measurements of Chlorine Atoms in A Plasma Reactor

1986 ◽  
Vol 68 ◽  
Author(s):  
Joda Wormhoudt ◽  
Alan C. Stanton ◽  
Albert D. Richards ◽  
Herbert H. Sawin
Keyword(s):  
Plasma Etching ◽  
Infrared Absorption ◽  
Ground State ◽  
Parallel Plate ◽  
Flow System ◽  
Plasma Reactor ◽  
Line Strength ◽  
Hyperfine Component ◽  
Pressure Discharge ◽  
Atomic Chlorine

AbstractInfrared absorption spectroscopy has been used to measure atomic chlorine concentrations over a range of plasma conditions in both Cl2 and CF3Cl discharges.These measurements were made utilizing the spin-orbit transitions in the ground state of atomic chlorine near 882 cm−1.The concentration studies were performed by passing light from a diode laser through a multi-pass (White) cell set in two opposed windows of a parallel plate plasma etching reactor.The plasma work was preceded by a laboratory measurement of the infrared absorption line strengths of the 2P1/2 ← 2P3/2 transition.This measurement was done in a known concentration of atomic chlorine produced in a low pressure discharge flow system by the reaction of Cl2 or HCl with excess fluorine atoms.These measurements resulted in an integrated line strength of 4.14 (±0.89) × 10−21 cm2-molecule−1-cm−1 for the strongest hyperfine component of the transition at 882.3626 cm−1.Measured atomic chlorine concentrations in Cl2 discharges varied between 0.2 and 8.0 × 1014 atoms/cm3, representing atomic chlorine fractions on the order of a few percent.The measured atomic chlorine concentrations increased approximately linearly with increasing power and pressure, and increased with increasing frequency above approximately 1 MHz.Below 1 MHz, the atomic chlorine concentration was relatively independent of frequency.

Plasma sheath electric field strengths above a grooved electrode in a parallel-plate radio-frequency discharge

1999 ◽  
Vol 27 (1) ◽  
pp. 70-71 ◽  
Author(s):  
U. Czarnetzki ◽  
G.A. Hebner ◽  
D. Luggenholscher ◽  
H.F. Dobele ◽  
M.E. Riley
Keyword(s):  
Electric Field ◽  
Radio Frequency ◽  
Parallel Plate ◽  
Plasma Sheath ◽  
Radio Frequency Discharge ◽  
Field Strengths

Theoretical and Computational Problems in Modeling Glow Discharges

1986 ◽  
Vol 68 ◽  
Author(s):  
David B. Graves ◽  
Klavs F. Jensen
Keyword(s):  
Plasma Reactor ◽  
Physical Structure ◽  
Plasma Sheath ◽  
The Self ◽  
Rf Discharge ◽  
Fluid Equation ◽  
Complex Interactions ◽  
Self Consistent ◽  
Self Consistent Field ◽  
The Many

AbstractIt is desirable to develop detailed models of glow discharge chemical reactors in order to understand the many complex interactions that govern reactor performance.One important part of an overall model of the plasma reactor is the description of the discharge physical structure including charged particle densities, energies and the self-consistent electric field.The continuum or fluid equation approach to this problem is presented in this paper and potential problems with this approach are discussed.Results from recent simulations of a 13.56 MHz rf discharge are presented.The behavior of the electrons in the quasineutral plasma and their interaction with the self-consistent field are highlighted.It is shown that the rf power dissipation peaks at the plasma-sheath boundary, and the implications of this for the validity of estimates of mean electron density from equivalent rf rcircuit models is discussed.

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