Experimental Facilities Division Oak Ridge National Laboratory March 2005 ARCS Update Doug Abernathy ARCS Instrument Scientist March 20, 2005 Joint IDT Meeting Pasadena, CA
Dec 22, 2015
Experimental Facilities Division Oak Ridge National LaboratoryMarch 2005
ARCS Update
Doug AbernathyARCS Instrument Scientist
March 20, 2005
Joint IDT Meeting Pasadena, CA
Experimental Facilities Division Oak Ridge National Laboratory2
March 2005
– a wide Angular-Range Chopper Spectrometer
Intended for study of atomic-scale dynamics in the thermal and epithermal range with single crystal capability.
IDT headed by Brent Fultz Scientist : Doug AbernathyEngineer: Kevin Shaw
Moderator decoupled poisoned waterBeam line 18Source-sample 13.6 mSample-detector 3.0m
Lattice dynamicsEntropy and the effects of vibrational modes on stability and phase transitions of solidsExcitations in disordered materials; effects of nanoscale features on vibrational entropy and thermodynamic stabilityEquations of state from measurements of the phonon density of states as a function of temperature and pressurePhonons in correlated-electron materials; coupling of lattice and electronic degrees of freedom in high T c, heavy-fermion and mixed valence materials
Magnetic dynamicsHigh temperature superconductivity Crystal field spectroscopyLow dimensional systems; 1D quantum magnets and low-dimensional conductorsMagnetism in actinide materialsHeavy fermion magnetism and superconductivityMetal-insulator transitions in oxides
Chemical PhysicsDeep inelastic neutron scattering studies of hydrogenCharacterization of novel materials
Experimental Facilities Division Oak Ridge National Laboratory3
March 2005
ARCS Instrument Overview
Moderator
Shutter
Guides
Choppers
Sample
Detector Array
Experimental Facilities Division Oak Ridge National Laboratory4
March 2005
Instrument Parameters
• minimum /Ei < 2%
• Ei = 10 – 1500 meV• Lengths
– Moderator to T0 chopper 9.0 m– Moderator to Fermi chopper 11.6 m– Fermi Chopper to sample 2.0 m– Sample to Detector 3.0 m
• Neutron Guide– Tapered supermirror 3.6 θc (Shutter 2.5 θc )
• 26m2 of 10-atm 3He detectors covering 2.9 Sr– Span -30o – -3o, 3o – 140o horizontal, -30o – -3o, 3o – 30o vertical. – ~100,000 pixels
• Evacuated sample and detector scattering chamber (~70m3) lined with neutron absorbing ZHIP mix (~200 m2)
Experimental Facilities Division Oak Ridge National Laboratory5
March 2005
Instrument Performance
10 100 10000
2
4
6
8
(
=0)
/Ei (
%)
Ei(meV)
ARCS SEQUOIA HYSPEC CNCS
105
106
4 cm x 4 cm sample
n/cm
2 /s
SEQUOIA ARCS MAPSBest E resolution (elastic) 1.2% FWHM 2% FWHM 2% FWHM
Flux at best resolutionincident energy 50 meV
10104
n/cm2/s
15104
n/cm2/s
1.5104
n/cm2/s
Flux at 2% E/E (n/cm2/s) 45104 15104 1.5104
Horizontal angle range -30o to 60o -30o to 140o -20o to 60o
Vertical angle range -30o to 30o -30o to 30o -20o to 20o
0 5 10 15 20 25 300
-2
-4
-6
-8
-10
-12
-14
-16
Qx(Å
-1)
Qz(Å-1)
ARCS SEQUOIA CNCS HYSPEC
Experimental Facilities Division Oak Ridge National Laboratory6
March 2005
Technical Developments for ARCS to reduce risk
• Detectors in vacuum (SNS detector and DAS groups)– Eliminate large vacuum windows; tight space
• Improve sample change time using a vacuum isolation system (SEQUOIA)– Reduce pumpdown time for efficient operation
• New neutron absorbing material for tank - ZHIP mix– Reduce hydrogen scatter from binder; better outgassing
• Fermi and T0 choppers (SNS chopper group/SEQUOIA)– Explore current and new ideas to optimize performance and
safety• Single crystal operation
– Build sample environment with orientation capability• Shielding optimized for background (SNS neutronics group)
– Use state-of-the-art simulations to guide design
Experimental Facilities Division Oak Ridge National Laboratory7
March 2005
ARCS Scattering Chamber with Integrated Sample Isolation
0 2 4 6 8 1010-7
10-6
10-5
10-4
10-3
10-2
10-1
100
101
102
103
104
P (
Tor
r)
t (hours)
high rate pumps Roughing pumps
•Procurement process almost complete – expect contract next week
•Rotation stage on hold until other costs determined
Experimental Facilities Division Oak Ridge National Laboratory8
March 2005
Fermi Chopper
• SKF/Revolve chosen as supplier of magnetic bearing, motor and housing. ARCS responsible for slit package construction.
• 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– Final FEA analysis done – Boron-fiber composite chosen for absorbing slat material – Assembly jig and test pieces constructed at ANL (R. Niemann) and
being modified at SNS– Spin test has validate design for final production
• Delivery of systems foreseen for mid-2005 (not a time critical activity)
Experimental Facilities Division Oak Ridge National Laboratory9
March 2005
Fermi Chopper System
• Electrical and cooling connections issues resolved – final design approved.
• Translation table on order; it will be supplied to Revolve for testing of performance of Fermi choppers while mounted.
Experimental Facilities Division Oak Ridge National Laboratory10
March 2005
Fermi Chopper Slit Package and Body
• Finite element stress calculations in elastic range
• All material below yield stress
Experimental Facilities Division Oak Ridge National Laboratory11
March 2005
Fermi Chopper Assembly
• Assembly jig and procedure developed at Argonne
• Knowledge being transferred to new SNS chopper group members
Experimental Facilities Division Oak Ridge National Laboratory12
March 2005
ARCS Detector Developments
• 109 1m 8-pack module
• 2 short modules above and below beam
• Absorbing baffles designed to block cross-talk within 90°
Experimental Facilities Division Oak Ridge National Laboratory13
March 2005
ARCS Detector Developments
894 LPSDs received
Experimental Facilities Division Oak Ridge National Laboratory14
March 2005
ARCS Production Process
•Complete dimensional and electrostatic measurements•Assemble into 8 packs
Experimental Facilities Division Oak Ridge National Laboratory15
March 2005
ARCS
•Perform electronics tests•Perform tests with neutrons
Experimental Facilities Division Oak Ridge National Laboratory16
March 2005
ARCS Flood Pattern
Tube 4 Flood Pattern
Ratio ((A-B)/(A+B))
-1.0 -0.5 0.0 0.5 1.0
Cou
nts
0
100
200
300
400
500
600
•Confirm wire integrity•Measure endpoints
Experimental Facilities Division Oak Ridge National Laboratory17
March 2005
Resolution Measurements
•Measure resolution•Measure slope and offset
Experimental Facilities Division Oak Ridge National Laboratory18
March 2005
LPSD Position Linearity
• Linear fit: Y = -5.137 x 10-2 + 1.998 x 10-3 X
• LPSD response is linear
LPSD Test Number
Coefficient of Determination
4 .99987
5 .99997
7 .99995
8 .99999
Tube 5 Linearity
Position Along Tube (mm)
-500 -400 -300 -200 -100 0 100 200 300 400 500
Rati
o (
(A-B
)/(A
+B
))
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
When tests are completed 8 pack is ready to Install
Experimental Facilities Division Oak Ridge National Laboratory19
March 2005
ARCS Procurement Status Overview
Item Design Procurement Cost
Core Vessel Insert Done Installed $92,400
Shutter Insert Done Installed $59,610
Guide – shutter Done Installed $60,000
Guide – beamline Done Bidding period; install before CD-4 measurement
$260,000
T0 chopper Draft spec ~ 9 month delivery $261,000
Fermi chopper Done Expected 5/05 $410,000
Slit Package Assembly Done 4/05 $40,000
LPSDs Done All 1m tubes in $1,100,000
Electronics & Mounting Final testing 7/05 or as needed $600,000
Vacuum chamber – sample isolation, vessels & pumps
Done Contract 3/05
~1 year delivery
$1,900,000
Shielding – Poured-in-place Done Forms under construction $30,000
Shielding - Other Neutronic and safety evaluation ongoing
$1,000,000
Green: Committed $
Blue: Expected by 5/05
Experimental Facilities Division Oak Ridge National Laboratory20
March 2005
ARCS Project Controls
$0
$2,000,000
$4,000,000
$6,000,000
$8,000,000
$10,000,000
$12,000,000
$14,000,000
2001 2002 2003 2004 2005 2006
ARCS BA Plan ARCS Spending Plan ARCS Cum Funding
•Now using SNS system
•Monthly reporting to DOE
•Rebaselining effort underway
Experimental Facilities Division Oak Ridge National Laboratory21
March 2005
Recent activities and ongoing work
• DOE Construction Progress Review held August 9-10, 2004
– Closeout cited good working relationship among the project personnel
– Strong recommendation to adopt project controls as done for other instruments and updating of controlled documents (PEP, design configuration, specifications, etc.)
– Strongly endorsed sample isolation concept
• Contracts for scattering chamber and guide to be placed soon
• Clarification of sample area design needed (this meeting, neutronics calculations, safety issues with hydrogenous material)
• Re-evaluating project schedule and cost for the last 18 months of the project
Experimental Facilities Division Oak Ridge National Laboratory22
March 2005
Instrument Model Views