Advances in Si-GDP, Ge-GDP and Glass Capsule Fabrication · PDF file 2017-04-14 ·...

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Transcript of Advances in Si-GDP, Ge-GDP and Glass Capsule Fabrication · PDF file 2017-04-14 ·...

  • 1 IFT\P2017-018

    Advances in Si-GDP, Ge-GDP and Glass

    Capsule Fabrication

    M.L. Hoppe,1 M.E. Schoff,1 N.G. Rice,1 A.L. Greenwood,1 A.A. Tambazidis,1

    S.O. Kucheyev2

    1General Atomics, P.O. Box 85608, San Diego, California 92186-5608 2Lawrence Livermore National Laboratory, P.O. Box 808,

    Livermore, California 94550

    22nd Target Fabrication Meeting

    Las Vegas, Nevada

    March 12-16, 2017

    This work performed under the auspices of the U.S. Department of Energy by General Atomics under Contract

    DE-NA0001808 and by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and

    General Atomics IR&D Funds

  • 2 IFT\P2017-018

    1) Partially densified glass capsules from silicon doped

    glow discharge polymer (Si-GDP) for use in Pushered

    Single Shell (PSS) experiments

    2) Fully deuterated germanium doped (Ge-GDP)

    capsules - also for PSS experiments

    3) Improved route to manufacture glass capsule fill tube

    assemblies (CFTA’s) using the Si-GDP -> glass process

    4) Method for manufacturing machined “keyhole”

    GDP/Si-GDP dual layer capsules for shock-timing

    experiments

    5) Latest progress in expanding the range of glass

    capsules that can be made via the Si-GDP process

    Recent development efforts to be discussed

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    wall (µm)

    1995 Base

    1998 Drop Towe r

    2005 Si -GDP

  • 3 IFT\P2017-018

    Partially converted glass capsules with significant D

    enrichment for Single Pusher Experiments

    Si-doped

    GDP

    Pyrolyze

    in N

    2

    Sinter

    in He/O2

    1

    2

    PAMS Si-GDP/PAMS Si-GDP SiO 2

    2 3

    Shrinks ~35%

    Plan was to start from the Si-GDP to Glass Conversion process

    Phase I: Using normal dopants (TMS and T2B) show process will work

    Phase II: Replace TMS with DTMS and T2B with DT2B in GDP process

    Phase 1 Results: @ 490ºC

    Final Density 1.80g/cc

    Silicon Density 0.66g/cc

    OD ~1200mm; 11mm wall

    SIMS shows there was

    Hydrogen present but

    cannot say quantitatively

    how much

    1200 mm TMS = tetramethyl silane

    T2B = trans 2-butene

  • 4 IFT\P2017-018

    Decision: IR shows Deuterium lost during glass

    conversion

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    01,0002,0003,0004,0005,000

    IR Spectra

    Si-GDP (no D) (TMS; T2B; H2) Si-GDP (with D) (TMS; DT2B; D2)

    Wavenumber (cm-1)

    Project stopped/put on hold until further notice

    Wavenumber (cm-1)

    Partially converted Glass from Si-GDP (no D) Partially converted Glass from Si-GDP (with D)

    C-H

    C-D

    O-H

    O-H

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    Wavenumber (cm-1) Wavenumber (cm -1)

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    Pre-glass conversion

    Partial glass

    conversion

    Potentially of interest??

  • 5 IFT\P2017-018

    Deuterated Ge-doped GDP capsules

    fabricated for Single Pusher Experiments

    on NIF Phase 1) Replaced precursor gases H2 with D2; T2B with

    DT2B but keep normal tetramethyl germane (TMG)

    - Refine coating parameters using normal TMG first to

    minimize cost

    IR Spectra:

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    65011501650215026503150365041504650

    C-H

    C-D

    Post PAMS pyro

    1400 mm

  • 6 IFT\P2017-018

    Phase 2) Replaced final precursor gas Tetramethyl

    Germane (TMG) with deuterated TMG

    IR Spectra:

    C-D

    IR spectra of Phase II D-GeGDP layer is

    consistent with very high D enrichment

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    6501,1501,6502,1502,6503,1503,6504,1504,650

    Fully Deuterated GeGDP

    (3.7mm) on PAMS mandrel

    (12.5mm)

    C-D

    C-H (PAMS)

    (PAMS background removed)

    4500 3500 2500 1500 (cm-1)

  • 7 IFT\P2017-018

    3He NRA for deuterium profiling

    D(3He,4He)H1

    3He + D = 4He + 1H

    Q = 18.4 MeV

    Quantitative Deuterium content can be measured

    by Nuclear Reaction Analysis (NRA) with 3He beams

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    Channel

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    Energy (MeV)

    CD (DPS-5)

    SiCO Ge

    C(He3,He3)C

    diagnostics pulser

    D(He3,He4)H

    D(He3,H)He4

    g7387.rbs

    Simulated

    Channel 1,5501,5001,4501,4001,3501,3001,2501,2001,1501,1001,0501,000950900850800750700650600550500450400350300250200150100500

    C o

    u n

    t s

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    Energy [keV]

    D(He3,He4)H

    D(He3,H)He4

    Best NRA estimate

    indicates ~65% D

    enrichment for

    DGeGDP sample but

    error bar is still large

    Problems to address in upcoming

    NRA experiments

    • Beam-induced D/H loss

    • Noisy signal

    • Shells -> Geometrical effects

    Method calibrated using

    Deuterated polystyrene

  • 8 IFT\P2017-018

    Initial CFTA capsule drilling trials with Drop-Tower (DT)

    glass capsules had limited success

    Issues with DT

    Glass

    • Poor coupling of laser with

    Glass capsule

    • Irregular

    shaped holes

    • Micro-cracks

    common

    around hole Drop-tower Glass

    Capsule with laser hole

    Micro-cracks can lead

    to failure at pressure 50 mm

  • 9 IFT\P2017-018

    Capsules starting from Si-GDP overcame the issues

    encountered with Drop-Tower glass

    Laser hole drilled in Si-GDP mandrel prior to

    conversion to glass

    • Laser coupling with Si-GDP much better than DT Glass

    • Much more uniform and round hole shapes

    • No micro-cracks around hole

  • 10 IFT\P2017-018

    Machined Si-GDP/GDP capsules developed for

    Keyhole Shock-timing experiments

    Goal: Produce capsules consisting of GDP/ Si-GDP that

    can be machined without cracking or deformation

    4 Methods Considered:

    1) PAMS pyro followed by machining

    2) Machining followed by PAMS pyro

    3) Machining follow by removal of PAMS using Toluene

    4) Laser Drill small hole, short PAMS pyro, then

    machining

  • 11 IFT\P2017-018

    Substantial Issues with first three methods

    1) PAMS pyro followed by machining

    - Hairline cracks in Si-GDP layer. No

    machining attempted. Likely due to

    shrinkage difference between Si-GDP

    and GDP during PAMS pyro

    2) Machining followed by PAMS pyro

    - resulted in severely distorted capsule

    3) Machining followed by PAMS removal

    using Toluene - Shells very fragile and difficult to process

    1 mm

    Hairline cracks

  • 12 IFT\P2017-018

    Best route was laser drill small hole followed by short

    PAMS pyro and then machine

    Capsule after PAMS removal

    Capsule after machining

    Final Capsule after

    release from mount

    1 mm

    1 mm

    Laser hole

  • 13 IFT\P2017-018

    First attempt to make the thick walled glass

    capsules (>35 mm) resulted in shards and hemis

    450ºC air pyro

    Hemi post PAMS pyro

    Nearly intact inner glass

    capsule

    Interface generated at Si-GDP

    coating breakpoint

    Interface (above) and intact inner

    glass capsules (right) gave clues to

    changes to be made for next

    attempt

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    1 mm

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