Progress in the field of first mirrors

1
Progress in the field of first mirrors
A. Litnovsky for the First Mirror SWG
2
First mirror activity in the Russian Federation
Compiled by K. Vukolov
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
3
FM activity in RF 1. Choice of material and type
of mirrors 2. Development of technologies for
fabrication of high quality mirrors Mirrors 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
contract Finishing polishing by ion etching EU
contract 3. Study of mirror properties Laser
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 HC
films and reflectivity of metallic mirrors
K.Yu. Vukolov, this meeting
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
4

• Table of main results

A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
5
Investigations at IPP Forschungszentrum Jülich
A. Litnovsky for A. Kirschner, A. Kreter, S.
Droste, V. Philipps, P. Wienhold, D. Borodin
and TEXTOR Team.
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
6
Erosion and deposition surface models
Simple mixing surface model
Surface model of TRIDYN
plasma
plasma
interaction layer
layer 1
layer 2
bulk volume (tungsten)
layer N
7
Influence of substrate material on the deposition
efficiency
Necessity of a multi-layer surface model TRIDYN

layer thickness d
0.08

• ? multi-layer model necessary for
• thin layers
• high impact energies

0.06
pure carbon
C sputtering yield
0.04
0.02
simple mixing model
0
50
100
150
200
Electron temperature eV
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
8
Influence of substrate material on the deposition
efficiency
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)
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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Influence of substrate material on the deposition
efficiency
Modeling ERO code coupled with TriDyn
Comparison of modeling with experimental results.

• 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

A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
10
New Experiment with Striped C/Mo/W limiter Aim
Further Benchmark of the coupled ERO TRIDYN code
Influence of substrate material on the deposition
efficiency
Ideas ? Observe carbon background
deposition on different materials for the
direct comparison ? Use reproducible
discharges ? Expose the materials under the
same plasma conditions.
erosion - zone
Molybdenum
Carbon
Tungsten
deposition - zone
toroidal direction
Picture Harry Reimer
Courtesy S. Droste
Surface analysis is underway
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
11
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
On the photo Deposit thickness distribution on
the mirror exposed in DIII-D divertor Results of
calibrated SIMS measurements
? 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).
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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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.
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
13
Investigations performed in the University of
Basel and in TCV Tokamak
Compiled by G. De Temmerman
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
14
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
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
15
Substrate effect

• Test of different materials and different
  recessment distances

Distance below
Glow
Deposited
Number
Experiment
Material
the tile surface
discharge
thickness
of shots
(mm)
(hrs)
(nm)
Mo
1.3
223
24.5
Si
4
50
15.89
Mo
4
90.5
50
820
24
5
Si
Thickness determined by ellipsometry/SIMS/
profilometry Deposited layer consists mainly of
carbon and deuterium
Strong differences in the thickness measured on
Si and Mo samples under similar exposure
conditions
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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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.
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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Modified lower divertor in DIII-DDiMES and MiMES
MiMES

• 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.

MiMES Mid-plane Material Evaluation System
New shelf
DiMES
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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New mirror experiments in DIII-D
ROF Proposal
Aims
? 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 Sample
PFR

150oC
The possibility to test other mitigation
techniques
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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Modeling joint activities of ORNL (USA) and
CEA Cadarache (EU)
Compiled by J. Hogan
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
20
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.

A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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BBQ validation comparison
- 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
J Roth et al.,J Nucl Mater, 337-339, p.970, 2005
BBQ calculation of CD4 emission, using IR data
for Tsurf
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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Mirror Research at ANL (USA)
Compiled by J. Brooks and J. P. Allain
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
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Status/plans for ITER diagnostic mirror research
J.N. Brooks, J.P. Allain, A. Hassanein, M.
NietoArgonne 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.

25
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/(cm2sec), 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.

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Summary

• Significant progress is achieved in the RD 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.

A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006
29
Thank you
A. Litnovsky First mirror SWG Report, ITPA -10,
Moscow, April 12, 2006