1. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 ARCS Update Doug Abernathy ARCS Instrument Scientist March 20, 2005 Joint IDT Meeting Pasadena, CA

2. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 2 – 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 Abernathy Engineer: Kevin Shaw Moderatordecoupled poisoned water Beam line18 Source-sample13.6 m Sample-detector3.0m Lattice dynamics  Entropy and the effects of vibrational modes on stability and phase transitions of solids  Excitations in disordered materials; effects of nanoscale features on vibrational entropy and thermodynamic stability  Equations of state from measurements of the phonon density of states as a function of temperature and pressure  Phonons in correlated-electron materials; coupling of lattice and electronic degrees of freedom in high T c, heavy-fermion and mixed valence materials Magnetic dynamics  High temperature superconductivity  Crystal field spectroscopy  Low dimensional systems; 1D quantum magnets and low-dimensional conductors  Magnetism in actinide materials  Heavy fermion magnetism and superconductivity  Metal-insulator transitions in oxides Chemical Physics  Deep inelastic neutron scattering studies of hydrogen  Characterization of novel materials

3. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 3 ARCS Instrument Overview Moderator Shutter Guides Choppers Sample Detector Array

4. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 4 Instrument Parameters minimum  /E i < 2% E i = 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 θ c (Shutter 2.5 θ c ) 26m 2 of 10-atm 3 He detectors covering 2.9 Sr –Span -30 o – -3 o, 3 o – 140 o horizontal, -30 o – -3 o, 3 o – 30 o vertical. –~100,000 pixels Evacuated sample and detector scattering chamber (~70m 3 ) lined with neutron absorbing ZHIP mix (~200 m 2 )

5. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 5 Instrument Performance

6. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 6 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

7. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 7 ARCS Scattering Chamber with Integrated Sample Isolation Procurement process almost complete – expect contract next week Rotation stage on hold until other costs determined

8. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 8 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)

9. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 9 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.

10. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 10 Fermi Chopper Slit Package and Body Finite element stress calculations in elastic range All material below yield stress

11. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 11 Fermi Chopper Assembly Assembly jig and procedure developed at Argonne Knowledge being transferred to new SNS chopper group members

12. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 12 ARCS Detector Developments 109 1m 8-pack module 2 short modules above and below beam Absorbing baffles designed to block cross-talk within 90°

13. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 13 ARCS Detector Developments 894 LPSDs received

14. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 14 ARCS Production Process Complete dimensional and electrostatic measurements Assemble into 8 packs

15. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 15 ARCS Perform electronics tests Perform tests with neutrons

16. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 16 ARCS Flood Pattern Confirm wire integrity Measure endpoints

17. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 17 Resolution Measurements Measure resolution Measure slope and offset

18. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 18 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 When tests are completed 8 pack is ready to Install

19. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 19 ARCS Procurement Status Overview ItemDesignProcurementCost Core Vessel InsertDoneInstalled$92,400 Shutter InsertDoneInstalled$59,610 Guide – shutterDoneInstalled$60,000 Guide – beamlineDoneBidding period; install before CD-4 measurement $260,000 T0 chopperDraft spec~ 9 month delivery$261,000 Fermi chopperDoneExpected 5/05$410,000 Slit Package AssemblyDone4/05$40,000 LPSDsDoneAll 1m tubes in$1,100,000 Electronics & MountingFinal testing7/05 or as needed$600,000 Vacuum chamber – sample isolation, vessels & pumps DoneContract 3/05 ~1 year delivery $1,900,000 Shielding – Poured-in-placeDoneForms under construction$30,000 Shielding - OtherNeutronic and safety evaluation ongoing $1,000,000 Green: Committed $ Blue: Expected by 5/05

20. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 20 ARCS Project Controls Now using SNS system Monthly reporting to DOE Rebaselining effort underway

21. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 21 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

22. Experimental Facilities DivisionOak Ridge National Laboratory March 2005 22 Instrument Model Views