1 Progress in the field of first mirrors A. Litnovsky for the First Mirror SWG.

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Progress in the field of

first mirrors A. Litnovsky for the First Mirror SWG

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First mirror activity in the

Russian Federation

Compiled by K. Vukolov

A. Litnovsky First mirror SWG Report, ITPA -10, Moscow, April 12, 2006

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FM activity in RF:1. Choice of material and type of mirrors

2. Development of technologies for fabrication of high quality mirrorsMirrors with Rhodium nanocrystalline coating - N.V. Klassen, this meeting

Mo mirrors with nanocrystalline column coatings – A.V. Rogov, this meeting

Multilayered dielectric mirrors – I.I. Orlovsky, this meeting Large SC Mo mirrors – EU contractFinishing polishing by ion etching – EU contract

3. Study of mirror propertiesLaser test of Mo and Cu mirrors – V.V. Sannikov, this meeting

Sputtering, blistering

4. Deposition and cleaning Research on mirror cleaning in low temperature plasmas – G.T. Razdobarin, this meeting

Heating effect on deposition of H:C films and reflectivity of metallic mirrors – K.Yu. Vukolov, this meeting


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I)Table of main results

Activity Result

Large SC Mo mirrors (“Luch”, Podolsk, RF)Mo single crystals of 120-140 mm

Mirrors with Rh coating (IPP, Chernogolovka)

Mirrors with Mo coating (Kurchatov)

Plasma and ion treatment (Kurchatov)

Samples stable under sputtering

Mo mirrors stable under sputtering

Finishing polishing of metallic mirrors

Thermal and Neutron Tests of Multilayered Dielectric Mirrors (Kurchatov)

The mirrors resisted to neutronsup to 1019 n/cm2 and 250C heating

High power YAG-laser test of Mo and Cu mirrors (Kurchatov)

Durability of the mirrors under pulsed laser radiation

Research on mirror cleaning in RF discharge (Ioffe)Heating effect on deposition of H:C films (Kurchatov)

Potential tools for cleaning of in-vessel diagnostic mirrors


Forschungszentrum Jülichin der Helmholtz-Gemeinschaft

Institut für PlasmaphysikEURATOM Assoziation – FZJ

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Investigations

at IPP Forschungszentrum

JülichA. Litnovsky for A. Kirschner, A. Kreter, S. Droste,

V. Philipps, P. Wienhold, D. Borodin

and TEXTOR Team.




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interactionlayer

bulk volume

(tungsten)

e.g.: net-erosion

cW(t) cC(t)

C, WC, W

plasma

“Simple mixing surface model” “Surface model of TRIDYN”

plasma

layer 1

layer 2

layer N

e.g.: net-erosion

cW,1(t) cC,1(t)

C, WC, W

cW,2(t) cC,2(t)

cW,N(t) cC,N(t)

Erosion and deposition: surface models



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50 100 150 2000

0.02

0.04

0.06

0.08

Electron temperature [eV]

C s

pu

tte

rin

g y

ield

8A20A80Apure carbon

layer thickness d

“simple mixing model”

multi-layer model necessary for

• thin layers• high impact

energies

Necessity of a multi-layer surface model: TRIDYN

Influence of substrate material on the deposition efficiency




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graphite tungsten

4 %Local deposition

efficiency: 0.3 %

Experimental observations: 13C deposition efficiency from injected 13CH4 in TEXTOR


A. Kreter et al, Proc. of 32nd EPS Conference on Plasma Phys. ECA Vol.29C, P-1.014 (2005)




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“TRIDYN surface model“ vs. “simple mixing model”:► decreased local deposition efficiencies► stronger substrate dependence

TRIDYN surface model is closer to the observations from the experiment

Localldeposition efficiency

13C

experiment

ERO modeling with:

TRIDYN surface model

Simple mixing model

C 4% 2.8% 7.2%

W 0.3% 0.9% 6.3%

Comparison of modeling with experimental results.


Modeling: ERO code coupled with TriDyn




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New Experiment with Striped C/Mo/W limiter Aim: Further Benchmark of the coupled ERO – TRIDYN code

Picture: Harry Reimertoroidal direction

erosion - zone

deposition - zone

Carbon

Moly

bdenum

Tungsten


Courtesy S. Droste

Ideas: ● Observe carbon background

deposition on different

materials for the direct

comparison;

● Use reproducible discharges;

● Expose the materials under

the same plasma conditions.


Surface analysis is underway



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Investigations of first mirrors: Current activities

► Direct comparative test of single crystal (SC) and polycrystalline Mo

and W mirrors under erosion conditions: investigations are finished;

► Mirror tests in DIII-D divertor: mitigation of deposition.Deposit quantification with SIMS: done;NRA measurements of C and D on the mirrors;Modeling (collaboration with Jeff Brooks, ANL).

Left Right

4 nm (C)

Down

26.4 nm (C)

~ 91.5 nm (O)*105.6 nm (C)

47.8 nm (C)

On the photo:Deposit thickness distribution on the

mirror exposed in DIII-D divertorResults of calibrated SIMS

measurements




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Future plans: 2006


Tests of ITER candidate mirror materials and technologies;► Direct comparative test of SC Mo and Mo mirror with nano-coating in

controlled erosion conditions in the SOL of TEXTOR (collaboration with KI and

Univ. of Basel);

► Direct comparative test of SC Mo, Rh-coated and amorphous mirrors under

erosion conditions in the SOL of TEXTOR (collaboration with KI and Univ. of

Basel);

► Large Mo mirrors for ITER diagnostics (EFDA EU-RF contract)

Carbon transport and the mitigation of deposition on mirrors in a

diagnostic duct: ► Experiment with Periscope-Upgrade system.

Joint experiments: ► New exposure of mirrors in the DIII-D divertor (details later in this

presentation);

► Mirror experiments in the divertor and pump-duct of ASDEX-Upgrade:

presently being discussed.

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Investigations performed

in the University of Basel

and in TCV TokamakCompiled by G. De Temmerman


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Exposure of mirrors in TCV Exposure of mirrors in TCV • Mirrors located in the divertor region and recessed below the surface of divertor tiles, no direct contact with the plasma. Simulation of mirrors placed in diagnostic duct;

• No shutter installed at moment but the sample manipulator is electrically insulated from the torus;

• Tests of different candidate materials by pair.

Sample exposures were integrated over short campaign periods of 2-3 weeks, including He glow discharge conditioning


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Substrate effect Substrate effect • Test of different materials and different recessment distances

Strong differences in the thickness measured on Si and Mo samples under similar exposure conditions

Thickness determined by ellipsometry/SIMS/ profilometry

Deposited layer consists mainly of carbon and deuterium


Experiment Material Distance below the tile surface

(mm)

Number of shots

Glow discharge

(hrs)

Deposited thickness

(nm)Mo 1.3Si 15.89

Mo 4

Si24

4

5

50

50

223 24.5

820 90.5

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Mirror research at DIII-D:

status overview D.Rudakov, A. Litnovsky, S.L. Allen, J.A. Boedo,

R.L. Boivin, N.H. Brooks, M.E. Fenstermacher, M. Groth,

C.J. Lasnier, A.G. McLean, R.E. Moyer, V. Philipps,

P.C. Stangeby, G. De Temmerman, W.R. Wampler,

J.G. Watkins, W.P. West, P. Wienhold, C.P.C. Wong.


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A new divertor shelf has been installed;

Divertor diagnostics had to be adjusted for the new divertor level;

DiMES mechanism was modified;

New: capability to expose material samples using the mid-plane reciprocating probe drive.

New shelfDiMES

MiMES

MiMES = Mid-plane Material Evaluation System


Modified lower divertor in DIII-DDiMES and MiMES

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New mirror experiments in DIII-D

● To repeat the heated experiment at fixed

elevated temperature(150oC) using the existing

DiMES Mirror holder;

● If more machine time available, repeat the non-

heated experiment to study the reproducibility in

the new divertor. DiMES Mirror SamplePFR

150oC

Aims:

The possibility to test other mitigation techniques

ROF Proposal


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Modeling: joint activities

of ORNL (USA)

and CEA Cadarache (EU)Compiled by J. Hogan


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Validation tests for ITER mirror deposition model

J Hogan*, E Dufour+, P Monier-Garbet+, C Lowry+, E Tsitrone+, R Mitteau+,

* Fusion Energy Division ORNL, + DRFC, CEA-Cadarache

● Deposition on ITER diagnostic mirror depends on the initial rate of generation, transport in the SOL to the mirror and, finally, the local mirror deposition rate;

● A validated quantitative model for the initial generation rate is so far lacking;

● To develop this, the BBQ code is applied to model the complex TS CIEL environment, comparing with local measurements of CII / Da emission from zones in deposition and shadowed regions;

● Results- high Te regime (physical and self-sputter processes) reasonably well modeled;- low Te regime: chemical erosion (J.Roth et al. J. Nucl. Mater 337-339, p.970, 2005) shows low values, but inclusion of sources from intra-tile gaps leads to improved agreement;

A collaboration has started to use ERO code (A.Kirschner (IPP FZJ) et al. to model intra-gap processes.


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- Physical, self-sputtering values in range (more work to do on self-sputtering)- Chemical sputtering (D+ flux suppression model*) is too low, Inclusion of measured higher temperatures in intra-tile (gap) region raises Ychem

BBQ validation: comparison

* J Roth et al.,J Nucl Mater, 337-339, p.970, 2005

BBQ calculation of CD4

emission, using IR data for

Tsurf


10

10

10

Sputteryield

-3

-2

-1

Yphys (Voie 3)

YselfZ=6 (Voie 3)

10 20 30 40 50

Te(a) eV

Yself (Zone 3)

Yphys(Zone 3)

Channel 3

4

CIEL

R

10 20 30 40 50

10-4

10-3

10

Sputteryield

-2

Te(a) eV

Yphys (Zone 3)

Ychem(Zone 3)without tilegap effects)

Ychem (Zone 3)cases includingtile gapeffects

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Mirror Research at ANL (USA)

Compiled by J. Brooks and J. P. Allain


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Status/plans for ITER diagnostic mirror research

J.N. Brooks, J.P. Allain, A. Hassanein, M. Nieto

Argonne National Laboratory

10th ITPA TG on Diagnostics, Moscow April 10-14, 2006

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Erosion/Deposition of ITER diagnostic mirrors: Plans for Code/modeling & Experiments*

We can compute the particle and energy fluxes to the mirrors, and erosion/deposition, as an add-on to planned work on ITER plasma facing component plasma/surface interaction.

Key resources: Code Package OMEGA (edge/sol plasma, sputtering, impurity transport with LLNL), HEIGHTS Code Package (transient response).

We are developing the MC-Mirror code: Monte-Carlo D-T, He, Be transport from plasma, through ducts, to mirrors. Includes sputtering and reflection of/from duct boundaries. Includes helium neutral generation in edge plasma (via charge exchange of He particles reflected from the wall), transport to mirrors Inputs/Connection to MC-Mirror code from Package-OMEGA.) (with University of Wisconsin)

We can compute (via IMD code) the effect on mirror performance.

We can study experimentally, via ANL/PRIME facility, the effects of particles/heat on ITER candidate mirrors.

* Subject to funding.

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ANL Preliminary Tasks: IMD code

IMD (D.L. Windt, Comp Phys 12 (1998) 360) is a computational program that models the optical properties including: reflectance, transmittance, phase shifts and electric-field intensities of multi-layer films and multi-component surfaces;

IMD will be linked with particle-induced damage surface codes;

Preliminary scoping tests of a Au-coated (1.0 µm) mirror with various Be coating thicknesses using the IMD computational code;

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We couple our modeling capabilities with in-house experimental measurements

The Particle and Radiation Interaction with Matter Experiments (PRIME) facility includes:

– State-of-the art in-situ surface metrology (IMPACT experiment) that monitors the behavior of surfaces at various depth scales under high-flux ion irradiation;

– Several ion sources with fluxes 1011-1016 ions/(cm2*sec), 25-500 C, impact angles 0-65 degrees, 5-5000 eV;

– Species: H, D, He, C, N, O, Ne, Ar, Kr, Xe, and Sn; others: C60, Aun

– A full-scale, high-power laser system custom designed and tunable between 193-nm and 2200-nm;

– Up to three ion sources can be run simultaneously. Experience: We have studied extensively the role of energetic ions on

plasma-facing mirror performance used in EUV lithography; This expertise can be leveraged to further understand the role of

particles on first mirrors in ITER and to develop schemes of their protection.

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Example: Sn exposure results on grazing incidence Rh mirrors for EUV lithography

Sn is studied since it is primary EUV radiator candidate for EUV lithography; Experiments at Argonne measure time-dependent erosion rates, Sn implantation and

deposition and in-situ EUV reflectivity; Figure shows surface Sn fraction as Sn vapor is deposited on Rh mirror with about

20% loss of reflectivity at 13.5 nm and 15-degree grazing incidence.

0 5 10 15 20 25 300.5

0.6

0.7

0.8

0.9

1.0

1-1.5 Sn monolayers (~ 0.8 nm)evaporated on Rh mirror

0.75 x 0.81 = 0.61

absolute reflectivity ~ 0.75Measured ex-situ

IMD code: 0.5nm Sn/ Rh, R = 0.63

% o

f ini

tial r

efle

ctiv

ity

Sn exposure time (min)

15-deg +/- 2 deg incidence

0 5 10 15 20 25 300.0

0.2

0.4

0.6

0.8

1.0

surf

ace

Sn

frac

tion

Sn exposure time (min)

Sn on Rh

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Summary


● Significant progress is achieved in the R&D of mirrors for

erosion environment;

● Intensive research is ongoing in the field of mirror cleaning

techniques;

● The mitigation of the deposition at elevated temperatures is

proven to be a complex process, depending on exposure conditions;

● The choice of the substrate (mirror) material strongly influences

the deposition efficiency. This needs to be investigated in future

in more details;

● Good potential and interest in modeling of mirror performance in

ITER, made and planned experiments;

● Closer collaboration with PWI community on issues of common

interest.

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Thank you


1 Progress in the field of first mirrors A. Litnovsky for the First Mirror SWG.

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