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