Kinetics of species in decaying plasmas

RF plasma jet as a species source

Relaxation oscillatory discharges

Flowing afterglows in  N2 or N2/H2/CH4 mixtures

Recently a low frequency RF probe method  has been advanced  allowing to determine with spatial and temporal resolution  the temperature, concentration and the distribution function of electrons in the afterglow of the high voltage pulsed discharge.
 

Kinetics of species in decaying plasmas is a research direction related to the development of new sources and diagnostic methods useful in plasma processing of materials (treatment, etching, and deposition). Plasmas in both temporal and spatial relaxation have been investigated. Very long (a few meters) filamentary plasma are obtained in low pressure noble gases pulsed discharges. It has been developed new diagnostics methods for the determination of the electron and gas temperature and for impedance monitoring in the temporal afterglow plasma. Also it has been advanced a theoretical model in order to determine from the temporal distribution of the Balmer lines the partial pressure of the hydrogen impurities in neon afterglow.
 

- Universite Paris-Sud, Laboratoire des Physiques de Gases et des Plasmas
- University of Texas at Dallas ( Prof. C.B Collins)

A.Surmeian, C. Diplasu, C. B. Collins, G. Musa, I. Iovitz Popescu
"Determination of the Gas Temperature in the Afterglow of the Pulsed Discharge"
J. Phys. D: Appl. Phys., 30, 1341 (1997 )

A.Surmeian, C. Diplasu, C.B.Collins, G. Musa, I.I.Popescu
"Electron Temperature Measurements in the Afterglow PLasma of High Voltage Pulsed Discharge in Cesium Vapours"
J. Phys. D: Appl. Phys., 30 1755 (1997 )

A.Surmeian, C.Diplasu, I.Iovitz Popescu G.Musa,  C.B Collins
Population mechanism of the impurities in noble gas afterglow
SPIE 2461 ,10, (1995)

  C.B.Collins, C.Diplasu, ,A.Surmeian, G.Musa, I.Iovit Popescu
Axial focussing effect in long low pressure pulsed discharges
Rom. J.of Physics 42,63, (1997 )

A.Surmeian, C.Diplasu, C.B.Collins, G.Musa, I.Iovit Popescu
A method for determination of partial pressure of hydrogen impurities in the neon afterglow
Rom. Reports in Physics 49, 575, (1997 )

C.B.Collins, C.Diplasu, ,A.Surmeian, M.Ganciu, A.M Pointu, G.Musa, I.Iovitz Popescu
Long and intense constricted pulsed dischrges at low gas pressure
Rom. Reports in Physics 49,163,(1997 )

A.Surmeian, C.Diplasu, C.B Collins, G.Musa, I.Iovitz Popescu
The determination of the electron temperature in cessium afterglows
Rom. Reports in Physics 49,189,(1997 )

A.Surmeian, C.Diplasu, G.Musa, I.Iovitz Popescu
The afterglow quenching effect in high voltage ultrashort pulsed discharge
Annals  of University of Iassy -1999 in press

C.Diplasu, A.Surmeian, G.Musa, I.Iovitz Popescu
Temporal characteristics of noble gases breakdown in high voltage pulsed discharge
Annals  of University of Iassy -1999 in press
 

RF plasma jet as a species source

(project coordinator Dr. George Dinescu)
A capacitively coupled, RF excited plasma jet has proven high efficiency for generation of excited species being a promising species source for remote plasma treatments.
A new diagnostic method based on the effect of excited species on a small discharge probe operated in pulsed mode is under consideration for stationary afterglow plasma species study.

-Eindhoven Universiy of Technology , Equilibrium and Thermal Plasmas Group
(Prof. D.C. Schram )

G. Dinescu, E. Aldea, D. Bivolaru, G. Musa
"Investigation of species in flowing nitrogen afterglow by a discharge probe " in "Molecular Dynamics and Hypersonic Flows" ed. M. Capitelli, Kluwer Publishers, NATO ASI Series C: Mathematical and Physical Sciences, Vol. 482  515-524 (1996)
 
 Dinescu G, Aldea E, Bivolaru D, Musa G
Discharge probe characteristics in the flowing nitrogen postdischarge
 Balkan. Phys. Lett. 80,6,(1997)

G. Dinescu, E. Aldea, P. Boieriu, C. Ilie, G. Musa
The RF capacitive postdischarge as a source of active species
 Romanian Reports in Physics 47, 1-2 (1996)
 

E.Aldea, C.Tananse, B.Mitu, G.Dinescu
Flowing characteristics of a nitrogen plasma jet
Annals  of University of Iassy -1999 in press

C.Tanase, B.Mitu,E.Aldea, G.Dinescu, G.Musa
The study of capacitively coupled RF plasma jets by image processing methods
Annals  of University of Iass -1999 in press
 
 

Relaxation oscillatory discharges

(project coordinator Dr. Ion Mustata)
A new system, using relaxation oscillatory discharges, was investigated both electrically and optically in order to appreciate its ability in thin layers deposition and their subsequent etching. Also pulse simulations give the possibility to explain the temporal behavior of the plasma oscillation. By pulse relaxation plasmas we were able to increase by as much as 30 times the etching rates of aluminium layers (deposited by TVA method) in comparison with those obtained in dc plasmas.

  -Hokkaido University, Sapporo (Prof. Yosuke Sakai)

I.Mustata,C.Biloiu
 A possible way for DC discharge simulation.
Contr.Plasma Phys.38,(1998)
 
 I.Mustata,A.Popescu,A.Salabas,M.Cretu,F.Leu,C.Biloiu
On the relaxation glow discharge pulse generation mechanism
 in print in   Rom.Rep.Phys
 
 I.Mustata,C.Biloiu,M.Cretu,A.Slabas,G.F.Leu
AC supplied relaxation pulse discharge
Annals  of University of Iassy -1999 in press
 
 I.Mustata, C.Biloiu, G.Leu, A.Popescu, G.Musa.
The Current and Voltage Time Variation Simulation of the Relaxation Pulse Discharges,Generated by dc and ac Sources.
ICPIG-,11-16 July 1999,Warshaw,Poland.

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Flowing afterglows in  N₂ or N₂/H₂/CH₄ mixtures

 

(project coordinator Dr. Silviu Danut Popa)
 In a flowing afterglow system d.c. sustained in pure nitrogen or nitrogen-hydrogen-methane mixtures the behavior of plasma parameters and the temperature of excited species and their interaction with the tube wall has been studied by optical emission measurements.
 
 

- Universite Paris-Sud, Laboratoire des Physiques de Gases et des Plasmas
 

S.D.Popa, P.Chiru, L.Ciubotaru
Modification of nitrogen spectra in a flowing DC discharge
J. Phys. D : Appl. Physi. 31 (1998) L 53- L55

S.D.Popa, L.Hochard, A.Ricard
N₂(C) population in a flowing nitrogen discharge
J. de Physique III, 7, (1997) ,1331-1337

S.D.Popa. P.Chiru, L.Ciobotaru
Influence of the wall material on the active species deactivation in a flowing d.c. discharge
in print in J.Phys. D
 

S.D.Popa, P.Chiru, L.Ciobotaru
Spectral modification in a N₂-H₂ flowing d.c. discharge”
Annals  of University of Iassy -1999 in press