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