jozef stefan institute plasma laboratory ljubljana, slovenia chemical cleaning with neutral oxygen...
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Jozef Stefan Institute
Plasma laboratory
Ljubljana, Slovenia
Chemical cleaning
with neutral oxygen or nitrogen atoms
MMiraniran Mozeti Mozetičč
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Fast removal of HC deposits
Benign to CFC
No oksidation of metals
Mednarodna podiplomska šola Jožefa Stefana
•
Application of neutral atoms (O or N)
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Tokamak
Remote O – atom source
Connection tube
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
O atom source is inductively coupled RF plasma
1.2 kW
5kW
We are building 15 kW source
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
O atom density at 500W
Pressure
Ato
m d
ensi
ty
P - limited
p -lim
ited
- lim
ited
Pressure
Ato
m d
ensi
ty
P - limited
p -lim
ited
- lim
ited
These values are measured in a side tube. The density in the major discharge tube is 2x larger
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Connection tube is made from material with a low coefficient for heterogeneous surface recombination γ < 10-4
The transmission of the tube depends on • the recombination coefficient• gas drift velocity• length of the tube
Drift velocity is close to sound velocity (300m/s)
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
FLUID simulations
plasma
Connection tube
To pump
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Experiment fits the theory
Oxy
gen
ato
m d
ensi
ty
Tube length [m]
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Influence of effective pumping speed
8 m3/h 16m3/h
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Setup under construction
plasma
n = 4x1022m-3
n > 1x1021m-3
Experimental chamber
3m long tube Schott 8250
Roots 500m3/h
Rotary 100m3/h
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
Experimental chamber
O atom inlet
To pumps
Heatable sample holder
Oxidation probability depends on
• type of CH
• temperature
Jozef Stefan Institute,
Plasma
labDepartment of Surface Engineering and Optoelectronics
HC film prepared by magnetron sputtering in Ar + H2 (pretty hard coating)
nO = 1021 m-3