TORE SUPRA Association EURATOM-CEA Philipps, Huber, Schweer, Sergienko, Brezinsek, Mertens, Zlobinski & Grisolia, Hernandez, Roche, Pocheau, Davi, Semerok.

TORE SUPRA

AssociationEURATOM-CEA

Philipps, Huber, Schweer, Sergienko, Brezinsek, Mertens, Zlobinski&

Grisolia, Hernandez, Roche, Pocheau, Davi, SemerokDelaporte, Hermann, Vatry, Mercadier, Sentis

laser based diagnostics for :

• tritium inventory

• material (PFC) composition

• dust in situ measurments

WP of TEXTOR and Tore Supra

TORE SUPRAAssociationEURATOM-CEA

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







• Laser illuminated dust observation (LIDO) (Tore Supra, textor)



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 R&D 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 R&D work (TEXTOR) : extension to W based materials (bulk W and W layers )


Movable target holder

Quadrupol MS

Fast IR linear array

camera

Fiber coupling

TEXTOR Tokamak

Laboratory Device

YAG Laser

Material test facility 1

Optical diagnostic D (H/D ratio) D, Dγ, CD CII, CIII

Conditions: absorbed power: 70 kW/cm2, pulse duration: 2-4 ms, Surface temperature Ts ≈ 1800 K


Graphite EK98 target exposed to TEXTOR plasma, LIDS

measurement: 2.2x1017 H,D/cm2), ±30%







• Laser illuminated dust observation (LIDO) (Tore Supra)



Laser induced ablation spectroscopy (LIAS)

Method:1. Absorption of power, breaking of C bonds 2. Production of Jet beam ±5o with particle energies of a few eV3. Absolute measurement of induced line intensities4. 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 /sFull ablation of a-C:H layers on graphite and tungsten limiter

Laboratory: E ≈ 1 J, double pulse: t=10 µsEnergy distribution (ToF), species distribution, ionisation degree, formation of cluster, reproducibility (particles/pulse)Wavelength dependence for ablation (Nd:YAG, Ruby, Excimer)


580 600 620 640 660 6800

100

200

300

400

500

600

CII(678.4nm)

CII(658nm)H(656nm)CII(589nm)

1st laser pulse 0.25J/cm2, spot No2, #96692

2nd laser pulse 0.25J/cm2, spot No2, #96693

3d laser pulse 0.25J/cm2, spot No2, #96694

inte

nsity

/ a.

u.

wavelength / nm

Laser induced ablation (LIAS)

Tungsten test limiter with 140 nm a-C:D coating

Laser ablation has been demonstrated, but more R&D on reproducibility & quantification needed

Cooperation of TEXTOR team with Polish association


Hogan et al (2007)

VD1

VD2VD3

VD4

Laser impactFor calibration(TS PhD 2009 work)

consequences

Improvement of Spectroscopic measurements










Laser induced breakdown spectroscopy (LIBS)

Release process identical with LIASBut 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


Mercadier Hermann, CEA/CNRS, Marseille

Goal : compare Laser efficiency(all materials)

~40J/cm2


Mercadier Hermann, CEA/CNRS, Marseille

~25J/cm2


3 steps of spectra modeling:

1. Analysis assuming a uniform plasma

2. Analysis of a non-uniform plasma

3. Self-absorption of resonance lines

(optical thick case)

ne , T

r

ne , T

r

LIBS (Mercardier, Hermann, CEA/CNRS, Marseille)

Composition of the Ablated plasma!

T/C










Method:pulsed illumination of dust particles with high repetition rateObservation 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!!!


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!


Wall element Laser spot 1cm2

H observation Ø1m

Mirror laser focussing

Mirror H light collector Nd

:YA

G l

as

er

H

lig

ht

Wall element

Nd

:YA

G l

as

er

H light

Exposed area: 1cm2

Absorbed energy: 80 JPower: 20 kWPulse duration: 4 msDistance 10 mCoaxial observationTilting angle 3o

0.5 m on wall

LCFS


mirror

surface

Ablation

Laser

CCD camera

Beam splitter

Tunable pulsed laser

Speckle interferometry

Altitude [µm]

X [cm]

Y [

cm]

Shape variation Image

Depth crater ~ 10 to 40 µm (accuracy ~ 5µm)

X [cm]

Alt

itu

de

[µ

m]

X [cm]

Alt

itu

de

[µ

m]

(Gauthier PSI)


LASKArticulated armLaser Applications System Kit


Tool for RH system:• Ablation/Heating/Dust sampling/ LIBS/…• Vacuum Atm Pressure• High T° (operation 120°C)

TORE SUPRA Association EURATOM-CEA Philipps, Huber, Schweer, Sergienko, Brezinsek, Mertens, Zlobinski & Grisolia, Hernandez, Roche, Pocheau, Davi, Semerok.

Documents

laser induced plasma

textor plasma

main plasma slide

sentis laser

laser efficiency

association euratomcea

d coating laser ablation

dust observationlido