Folie 1

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• laser based diagnostics for
• tritium inventory
• material (PFC) composition
• dust in situ measurments
• WP of TEXTOR and Tore Supra

Philipps, Huber, Schweer, Sergienko, Brezinsek,
Mertens, Zlobinski Grisolia, Hernandez, Roche,
Pocheau, Davi, Semerok Delaporte, Hermann, Vatry,
Mercadier, Sentis
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Basic concept of a laser based diagnostic system
on a fixed location (portplug) and/or on RH
system suitable for

• Laser induced desorption spectroscopy (LIDS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced ablation spectroscopy (LIAS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced breakdown spectroscopy (LIBS)
  (Tore Supra)
• in-situ without main plasma
• Laser illuminated dust observation (LIDO) (Tore
  Supra, TEXTOR)
• in-situ with and without main plasma

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Basic concept of a laser based diagnostic system
on a fixed location (portplug) and/or on RH
system suitable for

• Laser induced desorption spectroscopy (LIDS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced ablation spectroscopy (LIAS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced breakdown spectroscopy (LIBS)
  (Tore Supra)
• in-situ without main plasma
• Laser illuminated dust observation (LIDO) (Tore
  Supra, textor)
• in-situ with and without main plasma

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• LIDS Status of work
• Laser induced desorption spectroscopy (LIDS)
• fast thermal heating of a single spot (d 3mm in
  TEXTOR)
• total desorption of H isotopes
• excitation of released H isotopes by main plasma
• absolute measurement of induced H? intensity
• determination of H isotopes inventory using
  conversion factors
• LIDS tested and demonstrated in 3 years RD on
  TEXTOR
• In situ time resolved measurement of fuel
  retention in C-based materials and deposits
• Lower detection limit 1- 5 1016 D/cm2
• Real time TEXTOR deposits measured up to about
  0.5 ?m ( 1 x 1018 D/cm2), but no upper limit

Next RD work (TEXTOR) extension to W based
materials (bulk W and W layers )
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Conditions absorbed power 70 kW/cm2, pulse
duration 2-4 ms, Surface temperature Ts 1800
K
Optical diagnostic D? (H/D ratio) D?, D?, CD CII,
CIII
Fiber coupling
Fast IR linear array camera
Quadrupol MS
Material test facility 1
Movable target holder
TEXTOR Tokamak
Laboratory Device
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Graphite EK98 target exposed to TEXTOR plasma,
LIDS measurement 2.2x1017 H,D/cm2), 30
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Basic concept of a laser based diagnostic system
on a fixed location (portplug) and/or on RH
system suitable for

• Laser induced desorption spectroscopy (LIDS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced ablation spectroscopy (LIAS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced breakdown spectroscopy (LIBS)
  (Tore Supra)
• in-situ without main plasma
• Laser illuminated dust observation (LIDO) (Tore
  Supra)
• in-situ with and without main plasma

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Laser induced ablation spectroscopy (LIAS)

• Method
• Absorption of power, breaking of C bonds
• Production of Jet beam 5o with particle energies
  of a few eV
• Absolute measurement of induced line intensities
• 4. Determination of released particle using
  conversion factors
• Status (FZJ )
• Q-switch Ruby laser
• TEXTOR E 15 J, tpulse 10 ns, 1,5 ?GW, ?694 nm,
  1 pulse /s
• Full ablation of a-CH layers on graphite and
  tungsten limiter
• Laboratory E 1 J, double pulse ?t10 µs
• Energy distribution (ToF), species distribution,
  ionisation degree,
• formation of cluster, reproducibility
  (particles/pulse)
• Wavelength dependence for ablation (NdYAG, Ruby,
  Excimer)

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Laser induced ablation (LIAS)
Tungsten test limiter with 140 nm a-CD coating
Laser ablation has been demonstrated, but more
RD on reproducibility quantification needed
Cooperation of TEXTOR team with Polish
association
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Improvement of Spectroscopic measurements
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Basic concept of a laser based diagnostic system
on a fixed location (portplug) and/or on RH
system suitable for

• Laser induced desorption spectroscopy (LIDS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced ablation spectroscopy (LIAS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced breakdown spectroscopy (LIBS)
  (Tore Supra)
• in-situ without main plasma
• Laser illuminated dust observation (LIDO) (Tore
  Supra)
• in-situ with and without main plasma

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Laser induced breakdown spectroscopy (LIBS)

• Release process identical with LIAS
• But spectroscopic observation of ablated material
  by laser induced plasma
• in between discharges
• well established method in material analysis (in
  gaseous atmospheres)
• application in vacuum also investigated
• ? Assess reproducibility and accuracy

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Mercadier Hermann, CEA/CNRS, Marseille
40J/cm2
Goal compare Laser efficiency (all materials)
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Mercadier Hermann, CEA/CNRS, Marseille
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LIBS (Mercardier, Hermann, CEA/CNRS, Marseille)

• 3 steps of spectra modeling
• Analysis assuming a uniform plasma
• Analysis of a non-uniform plasma
• Self-absorption of resonance lines
• (optical thick case)

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Basic concept of a laser based diagnostic system
on a fixed location (portplug) and/or on RH
system suitable for

• Laser induced desorption spectroscopy (LIDS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced ablation spectroscopy (LIAS)
  (TEXTOR)
• in-situ with main plasma
• Laser induced breakdown spectroscopy (LIBS)
  (Tore Supra)
• in-situ without main plasma
• Laser illuminated dust observation (LIDO) (Tore
  Supra)
• in-situ with and without main plasma

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Method pulsed illumination of dust particles
with high repetition rate Observation of
scattered light During discharge and in between
discharges (gas injection) After dust
mobilisation events (?) fast events (ELMS,
disruptions, mechanical vibrations) Need of
robust model!!!
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• Open questions
• link between dust in suspension and total in
  vessel dust
• consequences of forced gas flow
• However, useful technique to measure dust in
  suspension, sedimentation
• ? Give data for model validation!

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H? light
H? light
NdYAG laser
Mirror H? light collector
NdYAG laser
Mirror laser focussing
Wall element
Exposed area 1cm2 Absorbed energy 80 J Power
20 kW Pulse duration 4 ms Distance 10 m Coaxial
observation Tilting angle ?3o ?0.5 m on wall
H? observation Ø1m
LCFS
Wall element
Laser spot 1cm2
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Speckle interferometry
(Gauthier PSI)
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Laser Applications System Kit
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• Tool for RH system
• Ablation/Heating/Dust sampling/
• LIBS/
• Vacuum ? Atm Pressure
• High T (operation 120C)