Managed by UT-Battelle for the Department of Energy Current and Future Instrument Development...

Managed by UT-Battellefor the Department of Energy

Current and Future Instrument Development Projects at Oak Ridge

Lee Robertson

Instrument DevelopmentGroup

ORNL SNS/HFIR

Final NMI3 Meeting

Ajaccio, France

June 2008

2 Managed by UT-Battellefor the Department of Energy Presentation_name

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


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.



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8.3% 100 nm PS in D2O

10.7% 100 nm PS in D2O

2.8% 40 nm PS spheres in D2O

Test of SESAME setup on Asterix at LANSCE

Design and fabrication of the wedge shaped coils need for encoding the momentum transfer in the neutron spin.

samplecoil

coildetector

Asterix Beamline



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.



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.


Focus Area : Instrument Development Beamlines

SE

RG

IS/M

IEZ

E

SampleAlignment

Monochromatic: Imaging/O

ptics

Pulsed: Instru

ment Development/O

ptics

HFIR Development BeamlinesCold Guide #1 (CG1)Operational in November 2008


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)


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.


Focus Area: 3He Polarizers and AnalyzersIn-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.

Laser opticsCoils & Shield

Oven

3HeNeutron Beam


Focus Area: 3He Polarizers and AnalyzersWide-angle analyzer for HYSPEC

• Current: wide-angle quartz cell.• Current: uniform-field coils for use on the instrument. • Future: compact polarized gas filling station.

No stress point seen under polarized light

Depolarized gas recycling

Polarized gas transfer

Wide-angle analyzer

72% cell optimize at 90 meV

Time (hours)

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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

To dry pump

3He

4He

RegulatorGetter

Baratron

N2

Regulator

Baratron

Regulator

Baratron

Getter

Getter

To turbo pump

To filter cell

Polarize

Sealed cell preparation

Valved cell

Sealed cell preparation


Focus Area: Focusing Optics

Collaboration with Gene Ice (ORNL) to applyFocusing using Kirkpatrick-Baez mirrors onNeutron 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.


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.


Five Year PlanShort Term Goals:• Guide characterization and measurement setup (guide mouse)• Integrate phase space modeling with Monte Carlo techniques• Design and application of supermirror polarizers• 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

Managed by UT-Battelle for the Department of Energy Current and Future Instrument Development...

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