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Euratom-FOM

Erosion and deposition of Cin Pilot-PSI

Gerard van Rooij

The Pilot-PSI and Magnum-PSI team:J. Westerhout, G. Wright, W.A.J. Vijvers, A.E. Shumack, H.J. van der Meiden, R.S. Al, H.J.N. van Eck, B. de Groot, W.R. Koppers, M.J. van de Pol, P.R. Prins, L.W. Veldhuizen, A.W. Kleyn, W.J. Goedheer, N.J. Lopes C

: D.G. Whyte

: R. Engeln, D.C. Schram

: Forschungszentrum Jülich (TEC): S. Brezinsek

T E CAssociation Euratom-FOM

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM Experimental: Pilot-PSI

Source TargetB

Coils

pumps

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM Experimental: Diagnostics

CH spectroscopy

Target

Calorimetry on cooling water

Thomson Scattering at 17 mm in front of target

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GvR @ ITPA, Garching, May 2007

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Euratom-FOMExperimental: target exposure

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM Results: TS and Spectroscopy

422 426 430 4340

2

4

6

8

Inte

nsity

(a.

u.)

Wavelength (nm)

CH

H-

422 426 430 4340

2

4

6

8

Inte

nsity

(a.

u.)

Wavelength (nm)

CH

H-

Radius (mm)0 10-10

Radius (mm)0 10-10

Te (eV)

0

1

ne (1021 m-3)

0

1

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM Results: conditions at target

experimental settings determine conditions reproducibly!

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM

Results: erosion/deposition profile

20

0

-20

-40

Hei

ght

(µm

)

5 10 15 20Position (mm)

-15 -10 -5 0 5 100

4

8

12E

lect

ron

dens

ity (

×10

20 m

-3)

Position (mm)10 mm

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM

Results: erosion/deposition profile

Erosion ≈ 0.94 mm3

Deposition ≈ 0.47 mm3

50% redeposition (Vol.%!)

20

0

-20

-40

Hei

ght

(µm

)

5 10 15 20Position (mm)

~ 150 μm

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM

Results: comparing , Tsurf and Ptarget

1.5

1.0

0.5

0.0

Power to target (103W)

1.00.80.60.40.20.0Electron Density (10

21 m

-3)

5

4

3

2

1

0

Flux Dens. (x1024

/m2s)

1500

1000

500

0

Target Temp. (K)

from cooling water: 20 eV/ion integration over TS profiles

Measured bulk temp. Calculated surf. temp.

30 mm

4 mm

C

1.6 mm

TC

C t

arg

et

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM Results: Chemical erosion rate600 K

1400 K

CH band

surface temp. dependenceaccording to Roth formula

1

0

Rel

ativ

e E

rosi

on Y

ield

12001000800600Surface Temperature (K)

CH intensity normalizedto total flux

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GvR @ ITPA, Garching, May 2007

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Euratom-FOM Conclusions

• Exposures at flux densities of 1-5·1024 m-2s-1 demonstrated

• Calculated sheath flux agrees with power to target

• Flux density sets surface temperature up to ~1400 K

• Up to 50 vol.% redeposition observed

• (Preliminary) chemical erosion yield drops by factor 50 by elevating surface temperature from 600 to 1400 K