Status of Procurements for the ARCS Instrument

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Status of Procurements for the ARCS Instrument
ARCS Construction Project Review DOE
Germantown Aug. 9, 2004

• Doug Abernathy
• ARCS Hardware Project Manager

SNS Instrument Systems
Oak Ridge
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ARCS Prototyping Efforts

• Based on risks identified early in the project
  (March 2002 Baseline Review) several efforts were
  launched
• Neutronics calculations
• Prototyping detectors in vacuum
• Testing outgassing of neutron absorbers in vacuum
• Single crystal closed-cycle refrigerator
• Detector mounting scheme
• Total cost of the efforts (approximately)
• Hardware 250,000 (vacuum system, detectors,
  mounting system, CCR and goniometer, etc.)
• Labor 250,000
• About 4 of total project cost
• Many components will serve a purpose in the future

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Trade off Between Dose and Size for ARCS Beamstop
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5
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Beam Stop Comparison

• Early study used to determine reasonable sample
  position for SEQUOIA.
• Quantifies size vs. cost for Value Engineering
  purposes
• Case 4 and 5 are for more tungsten

Cost Weight (kg) Diameter (m)
Case 1 174,464 105,590 3.2
Case 2 174,464 105,590 3.2
Case 3 209,745 103,552 3.2
Case 4 775,898 74,742 2.4
Case 5 1,094,153 61,529 2.2
Based on Dose Rate Analysis of C. Slater and
Engineering analysis of R. Williams

• Updated calculations ongoing, but significant
  differences are seen due to a re-evaluation of
  the spectrum from the moderator (E. Iverson)

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New material for internal shielding ZHIP mix
After an extensive search lead by Ralph Niemann,
we have found a producer of the B4C CF2
material Dielectric Sciences, Inc. Chelmsford,
Massachusetts Contacts Jerry Goldlust, Steve
Rigby They have dubbed this Zero Hydrogen In
Product mix ARCS has contracted with them to
supply samples and design studies for our needs.
They are affiliated with an ISIS supplier for
crispy mix and will bid on supplying material to
the MERLIN instrument.
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ZHIP mix properties vs. crispy mix

• Binder typically 6 by weight (DSI says best
  workability)
• Good mechanical properties, low shedding of grit
• Easily put on Al backing
• Procedures worked out to get high density (1.9
  gm/cm3)
• Outgassing performance excellent compared to
  epoxy based mixture
• Neutronic performance comparable to standard
  crispy mix

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Outgassing measurements

• Used ARCS large test vessel
• Procedure (Rate-of-rise test)
• Load sample
• Pump T0 when Plt1mTorr
• At desired time, note pressure and close gate
  valve
• Wait dt 15s
• Note pressure
• Open gate valve
• Calculate dP/dt and qA

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ARCS Procurement Status Overview
Green Committed Blue Expected by 10/04
Item Design Procurement Cost
Core Vessel Insert Done At SNS 92,400
Shutter Insert Done In manufacturing 59,610
Guide shutter Done Expected 11/04 60,000
Guide beamline Draft spec 1 year delivery 260,000
Guide end Conceptual 30,000
T0 chopper Draft spec 9 month delivery 261,000
Fermi chopper Done Expected 2/05 410,000
Slit Package Assembly Under testing 12/05 40,000
LPSDs Done Expected 10/04 1,100,000
Electronics Mounting Final testing As needed 600,000
Vacuum chamber sample isolation, vessels pumps Draft spec Pre-bid meeting 6/04 Contract 10/04 1 year delivery 1,200,000
Shielding Poured-in-place Done SNS organized 30,000
Shielding - Other Neutronic evaluation ongoing 1,000,000
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Early Procurements Driven by Target Schedule

• Core vessel and shutter insert components
  procured through common SNS effort deliveries
  and testing on schedule
• Need for shutter guide and housing by Nov. 2004
  prompted a division of the guide procurement into
  different sections
• Shutter guide specified and procurement awarded
  to CILAS design review complete production
  started
• Beamline guide specification drafted expect
  award in Sept. 2004 with delivery 1 year later
• Guide end between Fermi chopper and sample is
  dependent on details of sample area design,
  performance gains depend on sample size and
  tolerance for divergence
• Shutter guide is an example of value engineering
  m2.5 chosen compared to nominal m3.6 original
  design

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Guide gain varying shutter guide coating
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Percentage loss varying shutter guide coating
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Fermi Chopper

• SKF/Revolve chosen as supplier other possible
  vendors are based in Europe and posed risks to
  efficient coordinated design
• Building on SNS prototyping experience, the slit
  package assembly will be designed and built by
  ARCS in collaboration with the SNS Chopper Group
  while the magnetic bearing specialists provide
  proven bearing and phase control plus housing and
  service connection
• Contract includes integrated testing of 3 chopper
  systems plus one additional rotor using the
  translation table that will allow for quick
  changes of resolution in operations
• Current slit package assembly activities
• Evaluation of possible absorbing slat materials
  complete 10B coated, 0.35mm thick material most
  absorbing but a less expensive boron-fiber
  composite may be adequate for lower energies
• Final FEA analysis underway
• Assembly jig and test pieces being constructed at
  ANL (R. Niemann)
• Spin test contract in place to validate design
  for final production
• Delivery of systems foreseen for early 2005 (not
  a time critical activity)

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Considerations for the ARCS first chopper area

• Purpose Reduce background at detectors by
  blocking beam when protons hit the target
• Eliminate unwanted neutrons both before and after
  desired incident energy
• Two types currently used as spallation sources
• Horizontal axis (ISIS Lujan) 30 cm Inconel
• Vertical axis (IPNS) inches Be
• Engineering study done to see feasibility of
  producing fast (gt120 Hz) choppers of both
  designs
• Magnetic bearings for speed and reliability
• Use FEA to guide design

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Vertical Axis T0 chopper scientific design

• Typical parameters
• Channel width min. 8 cm
• Channel width max. 10 cm
• Radius 25 cm
• Rotor weight 800 lbs.
• Operation at 30 Hz intervals
• Max. to be determined by detailed engineering
  120 Hz
• Open questions
• How much material really is needed in the beam at
  T0?
• Can crystal alignment be done with chopper
  operating?

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Geometric beam blockage for T0 choppers - Time

• Operating at 120 Hz with minimum of 30cm of
  Inconel in beam at T0 and phased for 1000 meV
  (vert. axis)

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Geometric beam blockage for T0 choppers - Energy

• Horizontal axis wide bandpass with high energy
  leakage
• Vertical axis beam blocked outside of incident
  energy

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Detectors

• Reuter-Stokes chosen from 2 bidders to supply
  LPSDs low risk based on existing instruments
  world-wide
• Cost is reduced by using SNS (DOE) supplied He-3
  roughly 20. This represents a contribution by
  SNS to the IDT budget.
• First 8 detectors received at SNS at the end of
  July. Once performance is confirmed remaining
  tubes will be manufactured by end of October.
• Placement of this order (probably 2nd largest
  single contract) represents a large reduction in
  risk to the project.
• Electronics and basic hardware for 8-pack
  detector modules are proven a final iteration
  on the design will be built to test for problems
  before production
• Evaluation of the frame to hold detectors within
  the vacuum vessel is ongoing using a mock-up at
  ANL
• There will be a smaller order (16 tubes) for
  special detectors around the beam exit design
  to be completed

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Design goals for the ARCS vacuum vessel

• Use SNS standard mounting flange for sample
  environment equipment accommodate sample motion
  esp. rotation
• Provide cryogenic vacuum for sample with quick (lt
  1 hr) changeout and good access for special
  equipment
• Minimize/eliminate neutron windows (thin Al),
  particularly near sample
• Mount and provide access to neutron detectors (
  turnaround several hours)
• Accept additional components variable aperture,
  oscillating radial collimator
• Include internal neutron shielding (crispy mix)
• Allow for external neutron shielding to block
  background
• Non-magnetic material 2m around sample
• Simple, turnkey operation of overall system

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ARCS vacuum vessel procurement status

• Strategy Look for a single vendor to produce a
  turnkey system, unless there is added value for
  separating sample and detector areas. Sample
  isolation area and detector area specifications
  to be sent together to interested parties.
• A vendor pre-bid meeting was held at SNS June 29,
  2004.
• Distributed preliminary specifications
• General goals as well as some engineering
  constraints were presented
• Tour of the target building and ARCS beamline
  area
• Total of 10 vendors attended or requested to
  receive the final request-for-proposals
• Discussion with one manufacturer indicates the
  gate valve concept is feasible, could be
  integrated into a sample vessel and tested
  separately
• Sample isolation is an important value
  engineering concept cost recover for one hour
  of SNS beamtime would be gt30,000

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Shielding

• Much of the shielding work has been waiting for
  more feedback from neutronic calculations for
  both dose rate (0.25mrem/hr) and background
• Initial SNS shielding studies performed by an
  external ORNL computational group
• Not necessary in tune with common practices in
  neutron scattering instrument
• Little added institutional learning
• Source file used was common to all instruments
  and overestimated high energies
• Decision taken for this effort to move to an SNS
  computational group
• Group is shared with target some delays while
  important issues were addressed
• Recently many beamlines are getting a second look
  with a more realistic source particularly
  advantageous for ARCS in near backscattering from
  target

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Personnel issues

• Additional effort will need to be procured for
  ARCS to meet its schedule goals
• Argonne effort will end with FY04
• Core instrument team at ORNL (scientist
  engineer) now
• Ramp up of intensive designer work makes long
  distance coordination more difficult
• More detailed interaction with SNS shared
  activities and target related installations
• Ralph Niemann will retire
• A statement-of-work for a designer is drafted
• Discussions for engineer time to replace R.
  Niemanns efforts coordinating chopper activities
  for ARCS underway