TARGET FABRICATIONS PROGRESS FOR

MEGAJOULE LASER EXPERIMENTS

12-16 MARCH 2017

22nd Target Fabrication Meeting | M. THEOBALD, JL. MIQUEL, L. JEANNOT, O. VINCENT-VIRY, C. CHICANNE, L. REVERDY, C. HERMEREL, C. DAUTEUIL, G. DE DEMO, S. MEUX, N. BOTREL, E. PECHE, P.VALOIS, A. BREVET, A. ZENTZ, L. GUILLOT, S. LOSSET, G.LEGAY, J.BRAY, N. CERMELLI, S. LE TACON, K.MOLINA, R. BOTREL, F. DURUT, S. ROCHER, R. CALAND, J. ANDRE, J. SCHUNCK, A. PINAY, A. GREGOIRE, I. GEOFFRAY, R. BOURDENET, M. MERLE, A. CHOBRIAT, O. RAPHAEL, P. MERILLOT, A. MAUBLANC, A.CHARPENTIER, A. CHOUX, V. DUTTO, L. BARNOUIN

OUTLINE

A short introduction of the LMJ facility status

Target fabrication progress:

We are developing a thematic approach on LMJ : a large panel of experiments will be done before

consolidating the ignition target design with dedicated experiments :

- A lot of different laser targets types are necessary

- Many fabrications developments (Microtechnologies, materials, characterization, assemblies…)

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LMJ FACILITY

ACKNOWLEDGMENTS TO J-L MIQUEL (PROJECT MANAGER) FO R HIS SLIDES

15 FÉVRIER 2017

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CEA | 10 AVRIL 2012

LASER MEGAJOULE MAIN CHARACTERISTICS

Target bayBiological protection : 2 m thick concreteTarget chamber Ø 10 m200 ports for laser beams and diagnostics

∅∅∅∅ 60m

H 38m

Ignition target

2 X 2 cones irradiation : 33°& 49°

Hohlraum length ~ cm

Capsule Ø ~ 2 mm

DT cryogenic layer

4 Laser baysGlass Nd laser, frequency tripled : λ = 0.35 µmDesigned for 240 beams, 176 will be installedLaser energy ~ 1.5 MJ, Power ~ 400 TWPulse duration : from 0.7 to 25 ns

The LMJ beamlines : most of the components have been qualified on the LIL prototype

M1SCF

Front end

Amplification Section

Transport, Frequency conversion and focusing

500 mJ

Spatial Filters

PEPC (plasma electrode

Pockels Cell)

4 passamplifiers

Deformable mirror

Angular multiplexing

15 kJ

Transport mirrors

TargetChamber

7.5 kJ UV50 µm15 ps

Frequency conversion & focusing system

Window + debris shields

1 & 2w beam dump

1 nJ

10 mJAmplifier

Regenerative cavity

Source

Phase plate

PAM

SID

Target bay : today equipment

RH TPS

Q28U

Q28L PW

beam

SID

Diagnostic Transfer Box

Intervention Vehicle

SIDDiagnostic :

3 m length30 cm diameter 150 kg weight20 µm precision

Chamber center Reference

7

LMJ schedule during the mounting phase

Three main activities are performed during the yearMounting of new bundlesActivation / qualification of the previous assembled bundlesPlasma experiments

Usually, only one shift is dedicated to experiments => 1 shot/dayWith both shifts, 2 shots/day have been obtained several time

In the next years : 50 Physics shots + 30 preparation shots (Diagnostic qualification, pointing, synchronization, …) per year

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

1st Shift

2nd Shift

Mounting

Experiments

Mounting

ExperimentsMounting

Mounting

ActivationQualification

Mounting

ActivationQualification

1-Hohlraum energeticsLaser plasma interaction,X-ray conversion ����Control of radiation flux

2-Fundamental dataEOS, Opacities…����Control of matter’s behavior under HP and HT

3-Radiation transportX-ray absorption, loss, reemission���� Control of energy transport

4-Implosion hydrodynamicsImplosion velocity, Shock tuning���� Control of compression5-Hydrodynamic Instabilities

Instabilities growth, turbulence���� Control of mixing

6-Fusion studiesThermodynamic conditions, initiation of fusion reactions ���� Control of ignition conditions

7-Ignition Study of different kind of ignition targets���� Control of DT burning

8-ApplicationsCoupling of an ignition target with another target���� Control of complex powerful system

The 8 experimental topics of the Simulation Program

TARGET FABRICATION

RECENT PROGRESS

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CEA | 10 AVRIL 2012

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WHAT IS TARGET FABRICATION ?

Specific materials

Machining

Assembly

Characterizations

Conception

Delivery

# 1 year

SPECIFIC MATERIALS : HOLHRAUMS

15 FÉVRIER 2017

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See J. Andre’s poster

Additive manufacturing prototypeGold holhraums but not only…

Holhraums with liners

Complete liner Localized liner

Cu 1,5µm

Au 30 µm Cu 1,5µm

Au 30 µm

Mandrel machining

Sacrificial layer deposition and laser machine

PVD coating

Sacrificial layer dissolution

Electro-deposition

Mandrel dissolution

2017 Omega EP Experiments2017 LMJ ExperimentsCu holhraums

Addition of PVD and electrolytic coatings New process developed

SPECIFIC MATERIALS : FOAMS & AEROGELS

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60 mg/cc20 mg/cc 80-100 mg/cc 300 mg/cc40 mg/cc

SiO2 aerogels:

275-300 mg/cc 500 mg/cc110 mg/cc 800 mg/cc70 mg/cc

≤ 2015

2016

2017

Ta2O5 aerogels:

CHx 25 mg/cc

Development of new densities:

Development of new fabrication techniques: Understanding aerogels aging process and environmental conditions influence on density:

Casting to avoid machining and assemblies

dens

ity

agingDensity reversibility under vacuum

vacu

um

vacu

um

vacu

um

SPECIFIC MATERIALS : METAL FOAMS

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See R. Botrel’s talk

Optimization in progress (PhD) to obtain satisfyingmechanical resistance necessary to

machine this kind of very fragile materials

Structure and relative density can be controlled with ion salt concentration and overvoltage

C3,

U3+

10V

C3,

U3+

1Vfoam density strongly depends on ionic salt concentration � electrolytic phenomenon

CATHODE

Au3+

Streamer

Gold foam

SEM pictures of gold foams (same magnification)

Streamers are thicker when increasing overvoltage → foams with higher densities

plasma Electrolyte[Au]=C

Applied Potential = U + Overvoltage

breakdown voltage

Low density gold : plasma electrolysis

SPECIFIC MATERIALS : METAL COATINGS

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See S. Le Tacon’s poster

Spin-coating and Sputtering

500 nm2000 nm500 nm

Glass

Sacrificial layer

Al

Pr

Al

Al

Pr

Al

Al

Pr

AlAl

Pr

Al

Release Laser machining Self supported disk ∅8 mm

Praseodymium thin films

Developments with some collaboration with

Al/Pr/Al

Issues :- Reducing residual stress- Ageing : encapsulation between efficient

aluminum layers

High stress

Low stress

Al

Pr

Surface mass (g/cm²) characterization

No deviation over 2 months under air :- Al barriers are efficient- No stress evolutionThese membranes will be experimented early 2018 @ L MJAl/Pr/Al

SPECIFIC MATERIALS : CAPSULES (MANDRELS)

Injection : Syringe pump replaced by pressure-based flow controllers: higher flow stability, retro-control on flow rate variations

Curing : • Setting and monitoring installation

parameters and fluorobenzene concentration � Software development

• Measuring fluorobenzene concentration all along the curing process in each bottle (Coated quartz crystal microbalance developed by CEA Le Ripault)

A943 PAMS shell meeting expectations (50% yield)

PAMS Mandrels : improve yield

SPECIFIC MATERIALS : CAPSULES (GDP)See G. Legay’s poster

169,9 µm thick CHSi 4%at.Roughness optimization

Yield before polishing 20%

Yield after polishing 45%

After GDP coating After polishing

First capsules without any bumpsSome “light” scratches are observed inherent to polishing

Other “new” GDP studies :- New dopants (poster)- Asymmetric capsules

Ongoing work : Master the outside shape to fit a specific function

MACHINING

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In-situ run out correction on UP lathe

Z

X

Y

ϕϕϕϕ

θθθθρρρρ

Development of custom spindle neck with X/Y adjustment

Development of combined “turning” / “milling” by µ-EDM

Investigation in µ-EDM Development of a custom µ-milling machine (4 axis)

Tungsten carbide holhraum

Use the full potential of each process

Applications : Foam & aerogel complex shape machining

Compliant design, sub-micron adjusting capability

Adaptation of existing process to more flexibility

Milling in Low density foam

Applications : Machining of “hard” materials (steel, Ta, W, B4C,etc. )

Applications :- Run out correction - controlled shift of revolution axis

1 mm

See J. Andre’s poster

MACHINING : LASER

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Foam over-thickness < 5 µm

Surface finishingExcimer laser Femtosecond laser

UV pulsed laser193 nm / 50 Hz / 30 ns

Ti:Sa ultrafast laser800 nm / 1 kHz / 150 fs

Removal of foams layers on the surface of metals

Low density materials shaping.Example of Ta2O5 0,5 g/cc

Top/bottom diam.:200 µm / 400 µm

Optimized laser & motion parameters+ Specific mask shape

Cutting of rare-earth samplesunder dynamic vacuum

Controlled thermal effect on the edge(prevention of oxidation)

ASSEMBLYSee O. Vincent-Viry’s talk

Recasting of

optical systems

and command

control /

measurement

software

Turrets

motorization

Fast turret

positioning

New assembly station prototype

To face increasing target complexity and further increasing targets production

Specific automated stations : membrane gluing

� Adapt assembly stations to new target geometries and increase reactiveness� Focus technicians on valuable operations & automatize assistance on repetitive actions� Secure assembly operations (minimize sample manipulations)

Sucking nozzle for cone manipulation

Sucking nozzle for spherical ½ hohlraum manipulation

Tools : additive manufacturing

CHARACTERIZATIONS

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Quelques exemples de caractérisations pour les ciblesObjectives : 1. Secure our means2. Increase performance3. Purchase or develop new means to answer to our needs

See L. Reverdy’s talkV. Dutto’s posterO. Raphael’s posters

Spheremapper

Confocal probes

Sample holder

Movingstages

Calibration samples to compare AFM heads

Thin film thickness cartographer

Opaque or transparent samples

3D measurements

Xray tomographer

CRYOGENIC PROCESS

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DEVELOPMENT OF 2 cryostats IN COLLABORATION WITH CE A GRENOBLE

Cryoteci – D 2 cryostat

• Cryo-thermometers calibration• Keyhole target validation (liquid D2)• Useful temperature range is 15K-25K.

• Pulse tube as cold source• Double thermal shield

� last adaptations in 2017� Tests on real target in 2018

MVT-S – DT cryostat

• DT ice layer conformation studies• Temperature range 10 – 25 K• Stability +/- 1 mK

� Command control, gripper and thermal shield optimization in progress

� Delivery planed in 2 years @ Valduc tritium facility

• Pulse tube tandem for better stability

See F. Viargues’ poster

TRANSPORT TO EXPERIMENTATIONS SITES

15 FÉVRIER 2017 | PAGE 22

2 mm

1 mm

1 mm HED physic studies

2 mm

DAMDTRISMCI

Commissariat à l’énergie atomique et aux énergies alternatives

Centre de Valduc| 21120 IS SUR TILLE

T. +33 (0)3 80.23.53.01| F. +33 (0)3 80 23 52 77

Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 01915 FÉVRIER 2017

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CEA | 10 AVRIL 2012

Thank you !