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Status of FNPB

Geoff Greene / Nadia Fomin

University of Tennessee

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Spallation Neutron Source at ORNL

•1.4 GeV protons, 60Hz

•LHg Spallation target -> neutrons

•H2 moderator

•17m SM guide, curved

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Target, Reflectors, and Moderators

Be reflector

Steel reflector

CryogenicH2 moderators

AmbientH2 0 moderator

Mercurytarget

Proton Beam

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Flight Path 13

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SNS Will Eventually Have 24 Neutron Flight Paths

1B - Disordered Mat’lsCommission 2010

2 - Backscattering Spectrometer Commission 2006

3 - High Pressure Diffractometer Commission 2008

4A - Magnetism Reflectometer Commission 2006

4B - Liquids ReflectometerCommission 2006

5 - Cold Neutron Chopper Spectrometer Commission 2007

18 - Wide Angle Chopper Spectrometer Commission 2007

17 - High Resolution Chopper SpectrometerCommission 2008

13 - Fundamental Physics Beamline Commission 2008

11A - Powder Diffractometer Commission 2007

12 - Single Crystal Diffractometer Commission 2009

7 - Engineering Diffractometer IDT CFI Funded Commission 2008

6 - SANS Commission 2007

14B - Hybrid Spectrometer Commission 2011

15 – Spin Echo

9 – VISION

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Flight Path 13

• 13A – UCN Beamline

• nEDM

• 13B – Cold Neutrons

• NPDGamma

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FNPB Performance Matches Model Predictions

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SNS is now fully operational

~9 months of scheduled beam delivery per year

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Reliability against schedule is quite good

Beam Delivery ~450 MWhrs/month

Accelerator Power typically ≥ 1MW and slowly increasing

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Required Data Collection

David estimates that we need ~ 80 FULL MW-days of LH2 data*to attain a statistical sensitivity of ~10-8 on Aγ.

This estimate includes current best estimates of flux, polarization, transmission efficiencies, choppers bandwidth, run cycle losses, etc.

This estimate does NOT include LH2 reliability

At 450 MW-hrs/month, this implies that we need ~4.2 calendar months of live LH2 data.

*An additional ~12 days of Al data is estimated to be required