Technology Development

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• Technology Development

Lance Cooley TD / SRF Development Dept. / SRF
Materials Group Leader
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Goals for SRF Materials RD

• Our job is to figure out how to advance the state
  of the art.
• Goal Advance the state of the art toward the
  2012 ILC goal (90 yield at 35 MV/m)
• This goal also satisfies performance goals for
  Project X.
• Goal Can we define and approach even higher
  limits?

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Baseline fabrication sequence
At niobium vendor
At cavity vendor
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Baseline processing sequence
Quench
FE
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Issues lurk at every step because the art is
based on recipes and not on understanding

• Raw material
• Niobium is not sheet metal Each batch is
  different!
• Grain texture affects later forming and chemistry
• Alternate Ingot slices (Lg gr)
• Forming
• Shear is required to maintain thickness shear
  bands promote dislocation etch pitting
• Keeping ductility imposes restrictions on raw
  material
• Welding
• Pits! Many mechanisms are plausible
• Tooling, vacuum artifacts
• Vendor experience varies
• Remove forming history?
• Alternate hydroforming

• Tuning Heat treatments soften metal, promote
  detuning
• Chemistry
• Acids are dangerous
• Acid reactions are very sensitive to process
  params, matl history
• EP does not obey classic science high flow is
  used
• Cavity surface is complex how to model and
  control?
• Alternate Non-HF process
• HPR
• Ablative What is being removed? Damaged?
• Assembly experience varies
• Diagnoses
• Cant touch RF surface!
• Repair in situ?
• ALD, etc. New! Whats the payoff?

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Optical inspection key breakthrough!
D. Sergatskov, C. Ginsburg FNAL
Thermometry locates hot spots
Hot spots correlate with location of defects
(pits)
Seeing the microstructure provides the feedback
needed to drive the materials science!
WELD
Hayano group, Kyoto Image enhanced by FSU
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Management to address issues

• FNAL cannot do everything therefore we
  coordinate a comprehensive array of 30 partners
  from academia, labs, and industry (next slide)
• Many will be supported with ARRA funds
• Primary reporting is via SRF Materials Workshop
• FNAL is organizer
• HEP, JLab, Cornell, FSU, MSU also on program
  committee
• FNAL maintains QA/QC to support fab and
  processing
• FNAL conducts some basic work and processing RD
• FNAL performs activities not easily done by
  partners
• Pre-weld, coupon, and cavity acid work
• HPR, assemble, and test
• Diagnostics, including T-mapping, optical inspx.,
  and ECS

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U.S. Materials RD Community
Cavity vendors AES Niowave (Roark) PAVAC Sciaky (
Foreign vendors)
Processing Science FNAL JLab Cornell ANL Ohio
State Northeastern Nevada-Reno Texas AM Black
Labs Interlaken VCU Penn. State ABLE
EP Cabot Faraday Inc
Niobium vendors ATI Wah Chang HC Starck (Foreign
vendors)
Mgmt. FNAL JLab Cornell
Surface Science FSU U Chicago IIT Maryland ANL-APS
William Mary Virginia Tech
Materials Science Florida State Michigan State
Northwestern UIC
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Ties with international materials community

• Participate on organizing and program committees
  for SRF Workshop, TTC, Thin Film SRF Workshop
• Integration with S0 and GDE periodic meetings
• Broader interaction with large conferences and
  journals
• ASC 2008 special session
• ICMC 2009 plenary

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Shepherding the Materials Community

• Labs role
• Steer the agenda, define issues
• Get samples to academics coupons and pieces cut
  from cavities
• Zero in on real defects ECS, optical
  inspection, T-map
• Develop processing do work, modify based on
  understanding
• Facilitate ideas get 1-cell cavities to SBIRs,
  labs, academics
• Drive vendor development buy cavities, transfer
  processes
• Test cavities from vendors and give feedback
• Academics role
• Provide understanding based on materials,
  physics, and chemistry
• Provide reality checks, define limits, describe
  mechanisms
• Industry role
• Define the fabrication and processing realities
• Engage in dialogues with academics and labs
• Deliver cavities Generate new ideas (SBIR)

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Means to fill the lab role

• Routes to understanding require control over all
  steps
• We have our own Nb supply and conduct QA
• Also supports procurements
• 1 ton eddy-current scanned by end of FY09
• RRR and other diagnoses
• SEM, Instron, CryoInstron (MSU)
• Coupons and single-cell forming welding done
  by us
• We do the weld prep and etch
• We presently rent Sciaky EBW
• We plan to buy and support an e-beam welder
  ARRA
• 1-cell inventory for RD / SBIR (16 3.9GHz 18
  1.3GHz)

• Dedicated single-cell chemical processing in IB4
  op. mid FY10
• TD investment to support SRF
• ANL facility busy with 9-cell production
• We need to vary parameters and try new ideas, too
• Dedicated lab area
• Dedicated HPR and assembly op. end FY09
• Dedicated single-cell test _at_ A0
• Now op. set up by 3.9GHz SRF
• IB1 VTS busy with 9-cell
• Tumbling machine op. June 09
• Enables non-HF cavity RD
• Diagnoses plan for dedicated optical inspection

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New coupon tools
New witness sample fixture
Same elliptical shape as 1.3 GHz cavity
Ready for draft and build
Fixture goes in-line with standard EP tool
Sample
New coupon EP tool
In operation
Heat exchanger for temperature control, pH
monitoring, pumped acid
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Single-cell RD FY09-FY12

• Approx. 50 cavities, 90 processes, and 125 tests
• See A. Rowe breakout talk
• Vendor qualification
• Niowave-Roark, Accel and AES 6 cavities from
  each
• Other N. America
• Tool / facility qualification
• ANL facility
• Single-cell VTS
• Tumbling machine at FNAL
• EP industrialization at ABLE
• Optical inspection benchmark NR-4

• Processing RD
• 2 ECS defect cavities
• 6 cavities planned study material variations
• then carbon removal
• 6 cavities - EP science
• Alternate
• 2 cavities - Large grain and single crystal
  cavities
• 6 cavities - Non-HF processing, tumbling, CMP
• Planned hydroforming
• New ideas
• 4 cavities - ALD cap
• ALD multilayer, Nb/Cu
• MgB2 cavities
• SBIR

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Single-cell chemistry area (op. late FY10)
Scrubber Neutralizer
Acid storage
EP Cabinet
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EP tool development
Prototype
Generation 2 EP tool
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Single-cell clean room and HPR (op. FY10)
Class 10 clean room
Location of HPR Shower Stall
Certification and training 5/20/09
HPR Pump
Dessicator for HPR mists
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Tumbling and non-HF processing
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Capabilities

• 100 coupon samples per year should saturate
  academics
• 30 single-cell acid processes per year late
  FY2010
• Limited by staffing, facility is capable of 50 or
  more
• Supplying qualified 1-cells requires ANL-FNAL
  at present
• 50 HPR 1-cell processes per year starting FY2010
• Excess capacity expected to support 9-cell work
• 30 vertical tests per year, staff shared with AD
• EP team, Diagnosis team, QA team, Alternates all
  meet present needs 2 postdocs to be added
• See A. Rowe talk for more details

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Example Rapid information return from academics
(Here Does pit morphology indicate how it
formed?)
Coupon EP1-1 210 total µm removed
FNAL Keyence 3D microscopy
Pit 1
RF side
Blue-to-orange depth 60 µm Is there a moat?
3 inches
Pit Row via stitching anaglyph _at_ FSU (Lee, Sung)
Carbon ??
Carbon ??
250 µm
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Example coordination of complementary
measurements validates observations
Pit in TE1AES004
Silicone molding was used to make a replica of
this pit
Profilometer 5 x 5 mm, 0.3 mm Dz FNAL
Replica shows a raised feature in the center seen
both by profilometer and Keyence 3D microscopy
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Example Understanding comes at high levels of
detail (Here understanding the impact of raw
material variability)
Prof. Tom Bieler, MSU Blue is good, Red is
ok, Green is bad SEM with Orientation
Imaging Abrupt changes in color may be bad
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Example Synergistic studies determine basic SRF
limits(Here possible explanation why low-T
baking improves cavities)

• IIT magnetic scattering (never considered
  before)
• Proslier et al., APL 92, 212505 (2008)
• Oxygen defects are magnetic (Cava et al., 1991)
• Chicago Nb2O5 formed after etching is defected
• Thus mild baking
• Thickens the sub-oxides and reduces scattering
• Heals defects
• Then Capping by ALD bake improves Nb
• Proslier et al., APL 93, 192504 (2008)

superconductor point-contact junction
X-ray photoelectron spectroscopy
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Example Materials community synergism produces
collective effort greater than individual parts
(Here Hydroforming)

• Main issue raw material (fine-grained annealed
  tubes)
• No single vendor could take this on big
  problem!!
• New advances at Wah Chang, Texas AM, and Nevada
  Reno make significant headway
• Not competition all ideas fit together and
  address main issues
• National effort now being organized, will
  initially use 3-cell DESY tool and then transfer
  to American Hydroforming for full 9-cell

Fine-grained tube produced by Wah Chang for Black
Labs
Single Crystal tube produced by Nevada-Reno
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Response to issues is broad and enthusiastic

• Raw material Forming
• Texture forming MSU, BL, TAMU
• Impact of forging history MSU, FSU, NWU, UC
• Alternate MSU, Niowave, FSU
• Ductility BL, MSU, TAMU, WahChang FNAL spec
• QA ECS 1-cell
• Standards OrSU, FSU
• Welding
• Pits FSU, MSU, IIT, NWU, UC, vendors coupons
  1-cells
• Tooling, vacuum, experience vendor round-robin
• Annealing etc multi-vendor 1-cells, also FNAL
  coupons

• Hydroforming MSU, UNR, BL TAMU, WahChang, DESY,
  Interlaken, Amer. Hydroforming,
• Chemistry
• EP science FNAL group, NWU Ph.D. thesis, ABLE EP
• Non-HF EP FNAL, Faraday Inc,
• Non-HF process FNAL tumbler Cabot,
  Northeastern
• HPR
• Plasma clean Dzubya M.S.
• Identify Field emitters ORNL
• Diagnoses / Repairs
• Augmented Opt. probe IIT Joint faculty, U
  Maryland
• Remelting
• ALD, etc. 6 1-cells planned

SBIR
SBIR
SBIR
SBIR
ARRA
Univ SRF
SBIR
ARRA
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Conclusions

• A synergistic, coordinated, and broad community
  has been mobilized and are producing exciting
  science
• SRF University will greatly accelerate the
  development of materials-based understanding
• It has been kept alive with small seeds and the
  investigators other resources previous main
  grants have lapsed
• FNAL will continue to shepherd workshop pace
  will double
• We are converting from processes based on recipes
  to processes based on understanding!
• Progress on basic SRF themes continues as well.
• FNAL SRF Materials Group internal RD topics
• Non-HF, Hydroforming (coord), EP science,
  coupons, laser remelting, diagnostic RD, EP
  processing, HPR, Vert. test.