Target Fabrication at AWE – status,

achievements and challenges

Mike Norman

AWE Target Fabrication Group, Aldermaston, Reading, Berkshire UK

RG7 4PR

mike.norman@awe.co.uk

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Presentation outline

AWE Target Fab Mission & Organisation.

Overview of current capabilities Materials Science

Production

Metrology

Engineering, Planning and Quality

Recent Target Fabrication highlights/challenges Warm Dense Matter

Charged Particle Stopping

Future Technical Challenges

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AWE Target Fabrication: Mission

AWE conducts HED laser-plasma experiments in support of code validation in a CTBT environment

AWE TF primarily supplies targets for the Orion laser ~ 1000 targets per year

Mostly planar target configurations

Multiple elements on single shot to exploit Long pulse-Short pulse combination (Orion multi-target mount)

Also support collaborative campaigns on NIF and Omega 10’s of targets per year

Complex geometries

Also supply materials and target components

Orion:

10 beams 500J ea 1-5ns pulse 351nm

1 beam 500J 0.5ps pulse 1053nm and,

1 beam 200J 0.5ps pulse 527nm or,

1 or 2 additional 1-5ns 351nm “Backlighter”

beams

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Group leader Target

Fabrication

Capability TL(EP&Q)

Engineering Trials mangers

Planning

Quality

Capability TL (Production)

Micro-engineering

Assembly

Capability TL (Materials Science)

Chemistry

Coatings

Characterisation

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Target Fab Delivery Organisation

Overall group strength: 23 including management team

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AWE Target Fab Capability – Materials Science

Foams

Chemistry

Sol-gel

Chemistry

Coatings

(metal & polymer)

X-ray Computed

Tomography

Materials Science

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AWE Target Fab Capability - Production

Assisted AssemblyManual Assembly

Laser

Machining

Precision

Machining

Production

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AWE Target Fab Capability - Metrology

Metrology

Video CMMWhite light

Interferometry

Scanning

Electron

MicroscopyX-ray CT

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Engineering, Planning and Quality (E P & Q)

E P & Q

Engineering

Design Quality

Planning Customer

(PI) Interface

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Warm Dense Matter (WDM) campaigns

Measuring Equation of State of materials at low temp/near-solid density by

isochoric heating of samples with short-pulse generated proton beam

Radiograph adiabatic expansion and measure starting temperature

(pyrometry)

3 separate assemblies fitted to

Orion multi target mount

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Absorption mount

assembly

Proton foil

assembly

Back lighter

assembly

Multi target mount

assembly

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Warm Dense Matter (WDM) 2

Al C-mount and sample Previously machined off-site, recently

demonstrated in-house machining with better finish.

Special mounting face for grid – tight tolerance

CH, samples coated in-house, Al, diamond bought –in.

Sample strips laser machined to 50µm width

Sample width measured on Nexiv

AM jig-aided manual assembly (bottom)

Proton foil assembly 0.25 mm dia Proton foil and

0.35mm dia Al filter foil mounted on Al ‘alignment foil’ giving 0.1mm spacing (see photo).

All laser machined in-house

Diameter, parallelism & separation measured on Nexiv

Design optimised for assembly on OGP

Gd Backlighter Assembly Bought-in foil, laser machined to

size in-house.

Large Cu shine shield (pyrometry)

Angle of shine-shield bend measured on Nexiv

AM jig-aided manual assembly

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134 Target assemblies of 12 types delivered for 3 week campaign starting 31/10/16.

Grid

Sample strip

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Charged Particle Stopping campaign

Investigate stopping in dense plasma of particles generated by capsule implosions

Development of secondary plasma stopping target - demonstrate uniform heating and

accurate diagnosis of conditions

To try and ensure uniform heating, TF requested to develop

PyN laid down in 5-10 µm stages using in-house parylene coater. Significant development required for cube release from substrate.

Buried PyC, Al layers coated by Scitech Precision

Bi backlighter coating developed and coated by AWE TF

Cubes cut from coated slides using eximer laser machining at Scitech

Thicknesses measured on Zygo white-light interferometer

Remaining dimensions measured on Nexiv

Targets assembled using OPG

Cubes are sized around 70µm – does not meet 50µm goal but well below 100µm.

“Squareness” limited by focal depth of the machining laser?

Charged Particle Stopping 2

SEM image of mounted cube

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25 secondary cube targets of 7 types delivered for 2 week campaign starting 30th Jan 2017

Cubes on substrate following

laser machining

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Future Technical challenges

We are all being asked to do things: “smaller, better, more often”. To

meet this at AWE we are being asked for;

Thinner material bond lines

Research programme this year has come up with several promising leads for

uniform sub-micron bond layers, both with and without adhesives.

Increased yields of foamed products

Good progress on this in the last year – see Gareth’s presentation

Multi-layered targets with features

Free-standing, LiF-supported or diamond-sandwiched

Different material types (transition metals)

Evaluating coating, electro-plating, machining as options

See poster by Sarah Shergold

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Acknowledgements

This presentation is entirely dependent on the dedicated and highly skilled teams within AWE Target Fabrication without whom none of this would be possible.

Thanks also to:

Our AWE PI community for their support.

Our collaborative colleagues at LLNL, LLE, STFC, LANL

Our commercial providers

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