Current and Future Instrument Development Projects at Oak Ridge

1. Current and Future Instrument Development Projects at Oak Ridge Lee Robertson Instrument DevelopmentGroup ORNL SNS/HFIR Final NMI3 Meeting Ajaccio, France June 2008

2. Focus Areas • New Instrument Concepts • Instrument Development Beamlines • Instrument Simulation / Design Philosophy • 3He Polarizers / Spin Filters • Focusing Optics • Guide Development • Magnetic Focusing and Beam Transport • Monochromator Development Presentation_name

3. Focus Area : Instrument Concepts SERGIS / SESAME (collaboration with Roger Pynn) Use spin-echo techniques to encode the neutron momentum transfer. Spin-Echo Resolved Grazing Incidence Scattering applies the techniques to reflectometry. Spin-Echo Scattering Angle MEasurement applies the technique to SANS (SESANS). The main advantage of this technique is the need for tight collimation for measuring small momentum transfer is eliminated. Also measurements are done directly in real space. Presentation_name

4. Focus Area : Instrument Concepts Test of SESAME setup on Asterix at LANSCE coil sample coil detector Asterix Beamline Design and fabrication of the wedge shaped coils need for encoding the momentum transfer in the neutron spin. Presentation_name

5. Focus Area : Instrument Concepts Current Effort: • Roger Pynn’s group is building a SESAME development beamline at LENS (Indiana Univ.) • We are building a SERGIS development beamline at the HFIR. • We have designed and are now fabricating the third generation of coils for spin-echo encoding the momentum transfer. Presentation_name

6. Focus Area : Instrument Concepts Other instrument types of interest are: • MIEZE (Modulated Intensity Experiment with Zero Effort) – We plan to build a MIEZE development beamline in the future, possibly in collaboration with Roland Gähler. • Neutron Imaging – We are building an imaging development beamline in collaboration with Hassina Bilheux at HFIR. Fine focus using K-B mirrors for studying biological systems. • Instruments that take advantage of repetition rate multiplication. Presentation_name

7. Focus Area : Instrument Development Beamlines HFIR Development Beamlines Cold Guide #1 (CG1) Operational in November 2008 Sample Alignment SERGIS/MIEZE Monochromatic: Imaging/Optics Pulsed: Instrument Development/Optics Presentation_name

8. Focus Area: Design Philosophy • There is a need to better integrate source/moderator development with beamline and instrument design. (FRMII and JPARC did a fairly good job, SNS and OPAL did OK) • Schedule, politics, and funding often drive us to specify the source parameters based on a cursory survey of generic instrument types we might want to build. Detailed instrument designs begin so late in the process that optimizing the source configuration becomes difficult. • At Oak Ridge, we are attempting to address this issue by fostering a stronger scientific link between the neutron scattering and source development groups. (STS2, HB2 cold source) Presentation_name

9. Focus Area: Instrument Simulations • We are working on better software tools to couple moderator/source design and optimization with that of the instruments. • We are developing “canned” simulation packages of the existing instruments for scientists to use when planning there experiments and analyzing their data. • We are working on new computational methods that will allow us to combine the ability to handle complex geometries with the insight one obtains from phase space analysis. Presentation_name

10. Laser optics Coils & Shield Oven Neutron Beam 3He Focus Area: 3He Polarizers and Analyzers • In-situ polarizer / analyzer • Completed: compact in-situ polarizer (developed and used at IPNS). • Completed: switching of +/– spin state using the adiabatic-fast-passage (AFP) technique. • Current: Analyzer for SNS magnetism reflectometer. • Future: Side-pumped in-situ system. Presentation_name

11. No stress point seen under polarized light Focus Area: 3He Polarizers and Analyzers • Wide-angle analyzer for HYSPEC • Current: wide-angle quartz cell. • Current: uniform-field coils for use on the instrument. • Future: compact polarized gas filling station. Polarized gas transfer Wide-angle analyzer Depolarized gas recycling Presentation_name

12. Focus Area: 3He Polarizers and Analyzers • SEOP-based polarized 3He filling station • Current: establish temperature, laser power, and alkali metal requirements. • Current: assembly and testing of gas-supply system. • Current: construction of gas-polarizing system Baratron To turbo pump Sealed cell preparation N2 Getter Regulator Polarize Baratron To filter cell Getter Regulator 3He Valved cell Baratron Getter Regulator 4He Sealed cell preparation To dry pump Presentation_name

13. Focus Area: Focusing Optics Collaboration with Gene Ice (ORNL) to apply Focusing using Kirkpatrick-Baez mirrors on Neutron scattering instruments. The mirror in the photograph will be used on the single crystal diffractometer at the SNS. We are also experimenting with the use of Wolter mirrors for focusing the neutron beam. Presentation_name

14. Focus Area: Guide Development • Materials science study of guide degradation and lifetime. • Optimize guide configurations for specific applications (parabolic, tapered, elliptic, ballistic). • Experiment with using capillary optics (developed for x-rays) for focusing the beam. • Experiment with various surface treatments (etc.) to improve the performance of supermirror coatings. Presentation_name

15. Five Year Plan Short Term Goals: • Guide characterization and measurement setup (guide mouse) • Integrate phase space modeling with Monte Carlo techniques • Design and application of supermirrorpolarizers • HFIR instrument development beamline (SERGIS, MIEZE, Imaging, Optics) • Advanced 3He polarization capabilities (in-situ pumping, filling stations) Intermediate Term Goals: • Research into guide stability (substrate deterioration, interface mixing) • Ability to fabricate small supermirrors for testing fabrication process • Explore sample polarization techniques (Hydrogen, etc.) • SNS instrument development beamline (TISANS, repetition rate multiplication, cross-section measurement, Optics, pulse-probe applications) Long Term Goals: • Propose new instrument concepts for SNS 2nd target station • Develop magnetic beam transport techniques • Develop magnetic focusing techniques • Capability to fabricate larger, more complex guide components Presentation_name