NEG coatings news
Oleg B. Malyshev
ASTeC Vacuum Science Group
STFC Daresbury Laboratory
Cheshire
UK
Deposition method
Planar magnetron deposition
Cylindrical magnetron deposition
Alloy target for NEG coating used:
- with planar magnetron in 2003
- with cylindrical magnetron in 2008
10th European Vacuum Conference Oleg Malyshev 3
SEM images of films (film morphology )
columnar dense
RBS (film compositions in bulk)
XRD of Ti-Zr-V film
(microstructure and morphology)
Region scan of XPS core levels of Ti, Zr, C and V of a Ti-Zr-V film
(surface composition and chemical bounding)
Set-up for NEG pumping evaluation in ASTeC VS lab.
Test chamber 1
(option)
Twisted wires vs. alloy target: CO pumping
1.E-02
1.E-01
1.E+00
140 160 180 200 220 240 260 280 300 320
Activation temperature, oC
CO
sti
ck
ing
pro
ba
bil
ity
TiZrV(twisted wires)
TiZrV (alloy wire)
TiZrV (alloy wire)
NEG composition: Ti, Zr, V, Hf
140 160 180 200 220 240 260 280 300 3201 10
3
0.01
0.1
1
Ti-Zr-V
Hf-Zr-V
Ti-Zr-Hf
Ti-Hf-V
Ti-Zr-Hf-V
Ternary and quatornaly NEG coating
CO st
icki
ng p
roba
bilit
y
140 160 180 200 220 240 260 280 300 3201 10
3
0.01
0.1
1
10
Ti-Zr-V
Hf-Zr-V
Ti-Zr-Hf
Ti-Hf-V
Ti-Zr-Hf-V
CO p
umpi
ng c
apac
ity
140 160 180 200 220 240 260 280 300 3201 10
4
1 103
0.01
0.1
Ti-Zr-V
Hf-Zr-V
Ti-Zr-Hf
Ti-Hf-V
Ti-Zr-Hf-V
Activation temperature [ C]
H2
stic
king
pro
babi
lity
Bakeout coating (STFC patent)
0.2-mm thick coating:
Insulation layer (alumina jet coating)
Conductive layer (two types)
Heat resistant Kapton or other insulator
Operation
6-12-24 V DC or 110-240 V AC
Adjustable to desired Tmax
Principle
Insulator
Conductive layer
Vacuum chamber wall
Insulator
Conductive layer
Conductive layer
Dielectric layer
U
U
Vacuum chamber wall
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