LENS OVERVIEW

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LENS OVERVIEW

• David V. Baxter

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Outline

• Why build a pulsed neutron source at a
  university?
• LENS How to build such a source.
• Links/opportunities for exchange with ORNL.

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The Spallation Neutron Source (SNS)
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?
5000 users
Reactor
Pulsed
Neutron Sources
1500 users
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What is LENS?

• Low Energy Neutron Source based on low-energy
  (p,n) and (p,pn) reactions (Eplt14MeV) in Be.
• The source will be tightly coupled to a cold
  moderator (e.g. solid CH4 at 4KltTlt22K).
• LENS will have a variable pulse width (from lt5
  ms to 1.0 ms or more).
• In long-pulse mode, LENS will have a
  time-averaged cold neutron intensity comparable
  to an existing national user facility (IPNS).
• Initial moderator studies early 2005
• Full power operation in mid-2006

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Missions
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Present Funding Profile
DOD
IU
21st
NSF
11 M to date
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LENS at IUCF
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LENS at IUCF
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Floor Plan-2005
Moderator studies
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LENS Future Opportunities

• Moderator materials and engineering
• Novel ideas in Instrumentation
• Materials Research
• NETI (Neutron Education and Technology
  Institute)
• An NSF STC application (5M/yr for 5-10 years)
• 6 Universities and 4 National Labs
• A focal point for bringing university-based
  researchers into neutron research.

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Target/Moderator/Reflector (TMR)
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Opportunities in Moderator RD

• Investigate new materials
• Alternatives to CH4 and H2 (mesitylene,
  methane-clathrate,)
• Metal hydrides (reflectors and/or moderators)
• Push the temperature envelope
• Ultra Cold Neutron moderators
• Prototyping of new moderator designs.
• Train students in the physics/engineering of
  neutron moderators

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The Importance of being Moderate NIST (reactor)
http//ncnr.nist.gov/coldgains
OLD
NEW
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B. Heuser
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Floor Plan-2007
PSI-Y
RERP III
Radiog.
SANS
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SANS revisited
Collimation
kf
ki
Qkf-ki gt 0.001 A-1
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Spin Echo SANS

• Encode momentum info in neutron SPIN!
• NO COLLIMATION NEEDED!
• Max length scale probed is set by the
• maximum B field 0.1T 4 microns!

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The measured quantity is the Polarization as a
function of magnetic field (B) and l
where
s is the fraction of scattered neutrons and Po
is the polarization without a sample.
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Other modes of y operation
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Conclusions

• LENS will be a unique facility
• Its missions provide important support to the
  development of neutron science in this country
• It will play an important role in future
  developments at SNS
• We need to strengthen ties between IU and ORNL to
  maximize the potential return from this NSF
  investment in the neutron sciences.