1 Status of FNPB Geoff Greene / Nadia Fomin University of Tennessee

2 Spallation Neutron Source at ORNL 1.4 GeV protons, 60Hz LHg Spallation target -> neutrons H 2 moderator 17m SM guide, curved

3 Target, Reflectors, and Moderators Be reflector Steel reflector Cryogenic H 2 moderators Ambient H 2 0 moderator Mercury target Proton Beam

4 Flight Path 13

5 SNS Will Eventually Have 24 Neutron Flight Paths 1B - Disordered Mat’ls Commission Backscattering Spectrometer Commission High Pressure Diffractometer Commission A - Magnetism Reflectometer Commission B - Liquids Reflectometer Commission Cold Neutron Chopper Spectrometer Commission Wide Angle Chopper Spectrometer Commission High Resolution Chopper Spectrometer Commission Fundamental Physics Beamline Commission A - Powder Diffractometer Commission Single Crystal Diffractometer Commission Engineering Diffractometer IDT CFI Funded Commission SANS Commission B - Hybrid Spectrometer Commission – Spin Echo 9 – VISION

6 Flight Path 13 13A – UCN Beamline nEDM 13B – Cold Neutrons NPDGamma

7 FNPB Performance Matches Model Predictions

8 SNS is now fully operational ~9 months of scheduled beam delivery per year

9 Reliability against schedule is quite good Beam Delivery ~450 MWhrs/month Accelerator Power typically ≥ 1MW and slowly increasing

10 Required Data Collection David estimates that we need ~ 80 FULL MW-days of LH 2 data* to attain a statistical sensitivity of ~10 -8 on A γ. This estimate includes current best estimates of flux, polarization, transmission efficiencies, choppers bandwidth, run cycle losses, etc. This estimate does NOT include LH 2 reliability At 450 MW-hrs/month, this implies that we need ~4.2 calendar months of live LH 2 data. *An additional ~12 days of Al data is estimated to be required