Date Instrument Systems ORNL SEQUOIA Overview Garrett Granroth (Instrument Scientist) David Vandergriff (Lead Engineer) ARCS/SEQUOIA IDT meeting March 20, 2005

Date Instrument Systems ORNL Outline Overview Progress –Procurement Status –Installation Status Specific items –T 0 chopper –Sample Area Magnetic shielding issues Summary

Date Instrument Systems ORNL SEQUOIA Overview T o Chopper GuidePoured In-Place Shielding Front End shielding Beamline shielding Fermi Chopper Sample Vessel Detector Vessel Detectors Get Lost Tube Beam Stop Shutter insert Core Vessel insert

Date Instrument Systems ORNL Instrument Parameters minimum  /E i < 1.2% E i = 10 – 2000 meV Lengths –Moderator to Fermi chopper 18.0 m –Fermi Chopper to sample 2 m –Sample to Detector 5.5 m 43m 2 of detectors covering 1.2 Sr –Span -30 o – -3 o, 3 o – 60 o horizontal, -30 o – -3 o, 3 o – 30 o vertical. – ~138,000 pixels

Date Instrument Systems ORNL Instrument Performance

Date Instrument Systems ORNL Location SEQUOIA

Date Instrument Systems ORNL SEQUOIA and ARCS Beam Stop Detector Array Sample Vessel Fermi Choppers T 0 Chopper Shutter Insert CVI ARCS Beamstop Get-Lost Tube Detector Vessel 10 m 8 m 2 m 5.5 m

Date Instrument Systems ORNL System Overview Beamline 17/18 “Pit” Area

Date Instrument Systems ORNL Conceptual Design Review – March 04 Shutter Insert Guide * on Order with CILAS – April 04 Critical Decision - 1 (Alternative Selection and Cost Range) approved by DOE (CD-1) – April 04 Preliminary Design Review – May 04 Core Vessel Insert * Installed – July 04 Guide Design Review – August 04 Post Doc Matthew Stone arrives at HFIR – August 04 IDT meeting – October 04 CD-2A and CD-3A (long lead procurements) approved – October 04 Shutter Inset Guide Installed – December 04 Engineer Mark Overbay joins the SEQUOIA team to work on Choppers – January 05 Detector Vessel and Sample Vessel Design Review – February 05 Shutter installed – February 05 IPR and CD-3 Review (all procurements) – March 05 Guide vendor selected – March 05 Joint ARCS /SEQUOIA IDT meeting – March 05 * Early procurement permitted because these items are time critical SEQUOIA Dates

Date Instrument Systems ORNL Instrument Procurement Progress T o Chopper GuidePoured in Place shielding Front End shielding Beamline shielding Fermi Chopper Sample Vessel Detector Vessel Detectors Get Lost Tube Beam Stop Legend: Awarded Vendor chosen Out for bid In next 6 months BOA component

Date Instrument Systems ORNL In-Monolith Component Installation Shutter Insert (Feb 2005) Core Vessel Insert (Aug 2004) Shutter Insert guide (Nov 2004)

Date Instrument Systems ORNL Core Vessel Insert Installed Aug Apr Beamline 17

Date Instrument Systems ORNL Shutter Guide and Insert Installation

Date Instrument Systems ORNL T 0 Chopper Vertical axis narrow band width design. –Background reduction –Max Ei = 2 eV Up to 180 Hz operation. –Constant 31 cm Inconel X-750 to block beam. Ultimate 160 ksi. Yield 100 ksi. –Eliminates need for bandwidth chopper. –Working closely with ARCS team –Simplifies shielding design –Approximate spin up times 5 min per increment of 30 Hz –Magnetic Bearings reduce maintenance frequency –Initial rotor analysis completed –Specification under preparation.

Date Instrument Systems ORNL Crystal alignment with T 0 chopper 4 steps in phase to match white beam operate at 31Hz to sweep profile 1/s

Date Instrument Systems ORNL Sample Area Design Vacuum Isolation during sample change out Standard Flange with Rotary options 1 Ton max weight for sample environment equipment Non magnetic material Ease of access for : Sample Change Fermi Chopper Change Cryogen Fills Shielding for : Personnel protection Background reduction Reduction of stray magnetic fields

Date Instrument Systems ORNL Sample area Top access port Sliding top cover Magnetic shielding Quench vent Jib crane Sample equipment Equipment shelf Sample Stick (oxford Magnet sized) Enclosure door

Date Instrument Systems ORNL Sample Area – looking up

Date Instrument Systems ORNL Sample Area Enclosure dimensions –108” w x 120” d –96” inside height –72” x 108” shelf Jib crane to lift sample environment equipment, Fermi choppers. Sliding door for access. Sliding top access port for top loading and “long” sample sticks. Mezzanine access on the ARCS side. Equipment lift to raise and lower sample environment equipment. Considerable coordination with the ARCS team!

Date Instrument Systems ORNL Magnetic field Policy General principal –Don’t generate stray fields that mess with other beamlines –Multiple Approaches 1.Meet low limit (50 mGauss proposed limit) 2.Negotiate with affected neighbors for a different limit Spin Echo is affected neighbor. They have calculations to show they need 50 mGauss. We have calculations that show we can’t meet 50 mGauss with a15 T unshielded magnet. 3.Management decides on an experiment by experiment basis if you can temporarily violate above points ‒Self shielding compensated magnets are under development

Date Instrument Systems ORNL Magnetic shielding - top Incident beam

Date Instrument Systems ORNL Magnetic shielding Front

Date Instrument Systems ORNL Cut from closest interference Plate on ARCS side makes matters worse Rounded edges don’t help in far field 5cm is ~ 200 layers of electric steel Need IDT’s opinion on the need for fields

Date Instrument Systems ORNL Summary Progressing on SEQUOIA –Guide vendor selected –Detector Vessel and Sample Vessel out for bid –Shielding, Fermi chopper, and T 0 chopper to go out for bid in the next 6 months –In monolith components installed A workable sample area has been proposed T 0 chopper allows crystal alignment Magnetic shielding – We need your input