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This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC

Overview of the Materials targets at NIFTarget Fabrication Meeting 2017

1P. Di Nicola, 1D. Lord, 1M. Hagan, 1L. Savage, 1B. Heidl, 1J. Ward, 1M. Bauer, R. Seugling, 1A. Nikroo, 1C. Panas, 2K. Bigelow, 1J. Nguyen, 1S. Kucheyev, 1K. Blobaum,1G. Mercado,

1N. Le, 1M. Meloy, 1C. Davis, 1C. Kumar, 3J. Nafziger, 1C. Castro, 2J. Hund.

1Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, CA, USA 955502Schafer Corporation, 303 Lindbergh Avenue, Livermore, California 94551

3General Atomics, P.O. Box 85608, San Diego, California 92186-5608March 13th, 2017

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NIF has performed more than 400 target shots in 2016

Shots and Target demand have more than doubled since 2014

0

50

100

150

200

250

300

350

400

450

2009 2010 2011 2012 2013 2014 2015 2016

Nu

mb

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of

Sh

ots

Fiscal Year

Yearly Historical Shot Count by Program

DiscoveryScience

National SecurityApplications

ICF/NIC

SSP-HED

Total NIF shots

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NIF has performed more than 400 target shots in 2016

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50

100

150

200

250

300

350

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450

2009 2010 2011 2012 2013 2014 2015 2016

Nu

mb

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of

Sh

ots

Fiscal Year

Yearly Historical Shot Count by Program

SSP-HED

Total NIF shots

Materials Program shots make up half the HED shots on NIF

HED Campaigns have been growing in terms of shots taken

and complexity of targets

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TARDIS

Strength

Materials campaign: 3 sub-campaigns

Complex targets producing critical data for Stockpile Stewardship Program at increased rate

Equation-Of-State (EOS)

Strength DriveStrength RT

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We are building more targets for Materials campaign:

Complexity went up along with quantity of targets: we had to re-think how we were producing these

Highly complex targets with usually several R&D steps during build

Challenges:— Glue-less bonding process for Pb or PbSb

with V— Coining ripples with Pb and PbSb— Glue layer uniformity and minimal

thickness— Non-standard processes— Critical assembly of components with very

large stand-offs

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Material Strength experiments measure the Rayleigh-Taylor growth of solid rippled targets

Challenges:

— Glue-less bonding for some samples (Pb/PbSb with V)

— Coining ripples

— Critical assembly of components with very large stand-offs

— Non standard processes (metrology, assembly, leak-testing)

Drive beams

Face-on radiography:

Data has to be protected

from LEH X-Rays by a large

and thick Gold ShieldRippled foil

Ablator and

reservoir

Drive beams

Backlighter laser

Backlighter foil

x-rays

Expected data

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We re-designed parts and re-engineered of the target assembly and metrology process:

We developed a robust sample fabrication process,improved robustness of the assembly,

reduced costs and fabrication time while increasing yield

Glue-less bonding process for Pb or PbSb with V to fabricate the substrate to be coined

(See Coining Ripples on Metal Sample for High Energy Density

Targets, J. Nguyen, Poster session I)

Coining ripples(See Coining Ripples on Metal Sample for High Energy Density

Targets, J. Nguyen, Poster session I)

Improvement of the 1mm thick Gold shield — Assembly time: 6 days 3.5 days with increased

reliability on assembly— Metrology time: 3 days 1 day

(See Integrated Shield Design Improvements for Materials Strength

Targets, D. Lord, Poster session I)

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Melting and solidification are the largest rheological transitions a material can undergo

H2O With Strength

H2O Without Strength

Solid

Diffraction

Signal

Liquid

Diffraction

Signal

A platform was developed to use X-ray diffraction as a probe for melting TARDIS

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Drive:

16 beamsX-ray source:

24 beams

VISAR:

Determines

pressure

Diffraction

peaks

'Catcher'

Four SiO2 windows

(1st two shatter)

TARDIS platform:

Sample:

1: Ablator

2: 2 µm gold

3: Pusher

4: Sample

5: Window

1 23

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TARget Diffraction In-Situ diagnostic for x-ray diffraction experiments on NIFIt combines the target sample and the image plate housing

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Images of a fully assembled TARDIS target (sample and backlighter housing )

Front view (laser side)

Backlighter

(standoff = 35mm)

Sample

TARDIS, inserted into the Target Alignment

Sensor (TAS) in the NIF target chamber

TARDIS is a big device alignment clearances are small and tolerances are tight.More targets big optimization effort

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TARDIS challenges and achievements: we have improved the yield

We have improved the yield on glue layers by 25%

Glue layers: a lot of effort was put into developing and improving a robust process for multi-layer samples (item4 was made by stacking Ta and Pb layers)

Glue layers: effort benefited every type of glue layer, reducing out-of-specs glue bonds dramatically

(See Optimizing the TARDIS diffraction target Platform, B. Heidl, Poster session I)

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Sample:

1: Ablator

2: 2 µm gold

3: Pusher

4: Sample

5: Window

Glue bond requirements:

Ablator to Pusher: <1.5um or <3um

Pusher to Sample: <1.0um or <1.5um

Sample to Window: <1.0um or <1.5um

Ta-Pb multi layers

Cross-section before improvement Ta-Pb multi layers

Cross-section after improvement

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TARDIS challenges and achievements: we have reduced the production time

We have reduced the overall fabrication process by up to 60% while improving the reliability of the build and data associated

Re-organization of the documentation, including target request documents and

drawings

— Serialization and standardization of components

— Assembly time: 2-6 days 2-4 days with increased reliability on assembly

— Metrology time and as-built documentation: 4 days 2 hours

(See Optimizing the TARDIS diffraction target Platform, B. Heidl, Poster session I)

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The EOS platform: challenges

- Machining performance of steps- Glue layer thickness and uniformity between ablator and stepped sample

20 22 24 26 28 30 32 34 36 380

2

4

6

8

Time (ns)

Free S

urface V

elo

cit

y (

km

/s)

Experiment

Preshot Prediction Pt data

VISAR

diagnostic

Drive beams

Drive beamsCu ablator

Step sample

Cu (ablator and steps

in one component)

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Variation in steps heights used to be the dominant source of uncertaintyEffort to reduce the step height variation reduced experimental uncertainties by > 2x

Improvements to target fabrication (machining and assembly) have reduced random uncertainties

(See LiF Fabrication and Physics Package Assembly for NiF's EOS Targets, M. Bauer, Poster session I

And Improved Manufacturing of Equation of State (EOS) Physics Packages using Diamond Turning (NIF), L. Savage, Poster session I)

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Step machining improvements have had a key role in reducing error bars for experimental data

(See Fabrication of Equation of State (EOS) Targets with Submicron Tolerances for the NIF, M. Lament, Poster session II)

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We have developed and documented a process to produce reliably thin and uniform glue layers (<1µm)

Improvements to glue thickness and uniformity removed shock data artefacts

(See Sub-Micron Glue Thicknesses for Laser Experiments, C. Davis, Poster session II

And Improved Manufacturing of Equation of State (EOS) Physics Packages using Diamond Turning (NIF), L. Savage, Poster session I)

~4 µm glue layer modifies the

structure of the measured shock waveStructure is absent for glue

layers < 1 µm in thickness

Special thanks to EOS Physics team (J. Eggert, D. Fratanduono, R. Smith)

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TARDIS

Strength

Conclusion

Improvements at all levels of target fabrication have allowed us to deliver high-quality targets to NIF to support SSP

Equation-Of-State (EOS)

Strength DriveStrength RT