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Measurement of reactor antineutrino disappearance driven by  13

Measurement of reactor antineutrino disappearance driven by  13. New results from all 3 this year. Steve Kettell Brookhaven National Lab NuFact 2013, IHEP, Beijing. Chooz, France. RENO , Korea. Daya Bay, China. Reactor Neutrinos. SNO, Super-K , KamLAND. Super-K, MINOS, T2K, NOvA.

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Measurement of reactor antineutrino disappearance driven by  13

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  1. Measurement of reactor antineutrino disappearance driven by 13 New results from all 3 this year Steve Kettell Brookhaven National Lab NuFact 2013, IHEP, Beijing

  2. Chooz, France RENO, Korea Daya Bay, China Reactor Neutrinos NuFact 8/22/13

  3. SNO, Super-K, KamLAND Super-K, MINOS, T2K, NOvA 23 = ~ 45° 13= 9 12 ~ 34° Neutrino Mixing UMNSP Matrix Maki, Nakagawa, Sakata, Pontecorvo Daya Bay, Double Chooz, RENO MINOS,T2K, NOvA • νe = cosθ13 (cosθ12 ν1 + sinθ12 ν2) +e-iδsinθ13 ν3 • νe  0.82 ν1 + 0.55 ν2- 0.16 ν3 NuFact 8/22/13

  4. Neutrino Mass Δm2sol=m22-m127.5x10-5eV2 Δm2atm~=|m32-m12|2.4x10-3eV2 • Neutrinos have mass • one small mass difference (solar) • one large mass difference (atmospheric) NuFact 8/22/13

  5. Neutrinos from Nuclear Reactors • Nuclear reactor fuel and subsequent fission fragments are neutron rich and decay by turning neutrons to protons and emitting antineutrinos. • They produce a lot of antineutrinos: 61020 e/s/3GWth • We detect antineutrinos via the inverse beta decay (IBD) reaction • Ee+ E - 0.8 MeV Expected Signal NuFact 8/22/13

  6. Measuring 13 with reactor neutrinos • Measure relative rates in near and far detectors to remove reactor flux uncertainties • Build functionally identical detectors to remove detector mass and efficiency uncertainties • Measure distances accurately • Measure detector mass accurately NuFact 8/22/13

  7. Three active experiments NuFact 8/22/13

  8. Daya Bay EH-2: Nov 5, 2011 6 antineutrino detectors in 3 halls  8 since Oct 2012 320 t + 320 t EH-3: Dec 24, 2011 6  2.9 GWth EH-1: Sep 23, 2011

  9. The RENO Experiment 6  2.7 16.7 GWth 16 ton, 120 m.w.e. Near Detector 290m 1380m Far Detector 16 ton, 450 m.w.e.

  10. Double Chooz Mid-2014

  11. Antineutrino Detectors ‘functionally identical’ detectors: Reduce systematic uncertainties Target mass measured to 3 kg (0.015%) during filling. 5m 20t Gd-LS target LS MO All detectors filled from common Gd-LS tanks. 192 8” PMTs: ~163 p.e./MeV. Reflectors improvelight collection and uniformity. NuFact 8/22/13

  12. R=1.35m R=1.7725 m Automated Calibration System 3 Automatic calibration units (ACUs) on each detector Top view R=0 • 3 sources in each ACU including: • 10 Hz 68Ge(0 KE e+ = 20.511MeV’s) • 0.5 Hz 241Am-13Cneutron source (3.5 MeV n without ) • + 100 Hz 60Cogamma source (1.173+1.332 MeV ) • LEDdiffuser ball (500 Hz) for time calibration • Temporary special calibration sources: • :137Cs (0.662 MeV), 54Mn(0.835MeV), 40K (1.461MeV) • n:241Am-9Be, 239Pu-13C Three axes: center, edge of target, middle of gamma catcher

  13. Muon Tagging System Dual tagging systems: 2.5 meter thick two-zone water shield and RPCs • Outer layer of water veto (sides and bottom) is 1m, inner layer >1.5m. Water extends 2.5m above ADs • 288 8” PMTs per near hall • 384 8” PMTs in Far Hall • 4-layer RPC above pool • 54 modules in near halls • 81 modules in Far Hall • Goal efficiency: > 99.5% with uncertainty <0.25% NuFact 8/22/13

  14. Prompt Antineutrino(IBD) event selection Delayed np→dγ Fast neutrons Signal window No additional prompt-like 400us before delayed and no delayed-like 200us after

  15. “Identical” Antineutrino Detectors Prompt Spectra near IBD far Expected ratio is 0.981 due to reactor core distance. Neutron Capture Time Gadolinium concentration is “identical” for the two detectors NuFact 8/22/13

  16. RENO Status • Data taking began on Aug. 1, 2011 with both near and far detectors. • (DAQ efficiency : ~95%) Near • A (220 days) : First q13 result • [11 Aug, 2011~26 Mar, 2012] • PRL 108, 191802 (2012) A • B (403 days) : Improved q13 result • [11 Aug, 2011~13 Oct, 2012] • NuTel 2013 Far • C (~700 days) : Shape+rate analysis • (in progress) • [11 Aug, 2011~31 Jul, 2013] B • Absolute reactor neutrino flux measurement in progress • [reactor anomaly & sterile neutrinos] C

  17. RENO Results • RENO has continued data-taking & data-analysis in a steady state, and reported a new result in March, 2013. • RENO obtained the first result in April 2, 2012. • A clear deficit in rate (7.1% reduction) • Consistent with neutrino oscillation in the spectral distortion

  18. Double Chooz NuFact 8/22/13

  19. Double Chooz New rate analysis with reactor rate modulation sin2213 = 0.097  0.035 NuFact 8/22/13

  20. Double Chooz NuFact 8/22/13

  21. Data Overview • Two AD Comparison: arXiv:1202:6181 • - Sep. 23, 2011 – Dec. 23, 2011 NIM A685:78 • - Side-by-side comparison of 2 detectors • First Oscillation result: arXiv:1203:1669 • - Dec. 24, 2011 – Feb. 17, 2012 (6 ADs) • - 1st observation of νe dis. PRL108:171803 • Improved Result: arXiv:1210:6327 • - Dec. 24, 2011 – May 11, 2012 • - 2.5x original data, CPC37:011001 • New analysis • - Dec. 24, 2011 – July 28, 2012 • - 4x original data; shape, m2ee analysis • Full experiment (8 AD) • - Oct. 19, 2012 – present A E B C Results described in this talk For details see Soeren Jetter in Friday 12:10 WG-1 Jiajie Ling talk at BNL http://www.phy.bnl.gov/~partsem/fy13/BNL_Ling_dayabay.pdf D NuFact 8/22/13

  22. Data Summary EH-1 EH-2 EH-3 Over 300,000 antineutrino events Consistent rates for side-by-side detectors Uncertainty dominated by statistics NuFact 8/22/13

  23. Total backgrounds are 5% (2%) in far (near) halls. Estimate 9Li rate using time-correlation with muon Backgrounds Simulated Am-C source neutron capture position Background uncertainties are 0.3% (0.2%) in far (near) halls. Constrain fast-n rate using IBD-like signals in 10-50 MeV Hot AmC source deployment NuFact 8/22/13

  24. Uncertainty Summary Absolute Relative Influence of uncorrelated reactor systematics reduced by far vs. near measurement. NuFact 8/22/13

  25. Antineutrino Rate vs. Time Detected rate strongly correlated with reactor flux expectations. • Predicted Rate: • Assume no oscillation • Absolute normalization is determined by data fit. • Normalization is within a few percent of expectations. NuFact 8/22/13

  26. Shape and mass splitting NuFact 8/22/13

  27. Daya Bay Status • Near Site Operations (6/11-12/11) • AD#1-2 comparison paper published • NIM A685:78 (2012) • First 13: March 8, 2012 Discovery of reactor edisappearance at ~2 km • Phys.Rev.Lett. 108:171803 (2012) • 615 citations (~1.5 per day) sin22θ13=0.092±0.016(stat)±0.005(syst) • Updated result (55139 days) June 6, 2012 • Chinese Physics C37:011001 (2013) sin22θ13=0.089±0.010(stat)±0.005(syst) • 6-AD (2-1-3) data (12/11-7/12) sin22θ13=0.090+0.008-0.009 • Full 6-AD data analysis (217 days, shape & m232) |mee2|=2.59+0.19-0.2010-3 • Final two ADs installed, calibration campaign completed 7-10/12 • Taking data with all 8-AD since Oct 19, 2012 NuFact 8/22/13

  28. Future Plans

  29. RENO’s Projected Sensitivity of q13 (5.6 s) (402 days) (~ 14 s) (5 years) (18 % precision) (7 % precision) • 3 years of data : ±0.007 (7% precision) • - statistical error : ±0.010 → ±0.006 • - systematic error : ±0.015 → ±0.005 2013. 3 ssyst=0.015 • Goals • - sin22q13 to 7% precision • - direct measurement of Dm231 • - precise measurement of reactor neutrino flux and spectrum • - study for reactor anomaly and sterile neutrinos (7 % precision)

  30. Double Chooz plans NuFact 8/22/13

  31. Daya Bay Plans • Measure of 13 with high precision • Measure mee2complementary to accelerator-based experiments. • Further scientific goals: • Measure reactor flux/spectrum: possibly resolve ambiguities in reactor predictions and anomaly. • Multi-year measurement of reactor flux throughout fuel cycles. • Measure neutron and spallation production for various muon energies across DB depths. • Run for at least 3 years (thru 2015) August 2012 8-AD run Expect to achieve mee2 precision better than 110-4 eV2 after 3 years. Projected uncertainty in sin22θ13<4%. Reduction in uncertainty will improve CP reach of LBNE. NuFact 8/22/13

  32. Accelerator experiments: — normal, — inverted, CP=0, 23=45 Reactor experiments: rate only, rate+shape, n-Gd, n-H Summary Daya Bay n-H coming soon RENO Double Chooz n-Gd n-H sin22θ13=0.090+0.008-0.009 |mee2|= (2.59+0.19-0.20)10-3 eV2 sin22θ13=0.100±0.010(stat)±0.015(sys) sin22θ13=0.109±0.030(stat)±0.025(sys) sin22θ13=0.097±0.034(stat)±0.034(sys) Electron neutrino contains 2 mass-splittings (3 mass states) and the large splitting agrees with that measured from muon neutrinos NuFact 8/22/13

  33. Backup NuFact 8/22/13

  34. NuFact 8/22/13

  35. Daya Bay Selected as one of Science’s top 10 breakthroughs of 2012. “…result suggests that in the coming decades neutrino physics will be every bit as rich as physicists had hoped…neutrino physics could be the future of particle physics — as the fact that neutrinos have mass is not even part of the standard model. If so, the Daya Bay result may mark the moment when the field took off.” NuFact 8/22/13

  36. Experimental Halls complete 12/24/11 Hall 3 (Dec 11) 900m Configuration until July 2012 Ling Ao 2 465 m 810m Ling Ao Daya Bay Hall 2 (Nov 11) Hall 1 (Aug 11) NuFact 8/22/13

  37. Definitive sin22θ13measurement • Important measurement of a fundamental parameter • Daya Bay will have the best measurement for the foreseeable future • Improve extraction of mass hierarchy and CP from accel. expts. • Overconstrain PMNS matrix thru precision measurement of sin2213 • Improve ultimate precision on JCPνand allow tests of unitarity Significance with which CP violation can be observed by NOvA+T2K+LBNE, as a function of the true value of CP. Observation of CP violation is equivalent to the measurement CP0,. The significance is calculated by minimizing over both the normal and inverted hierarchies, as the mass hierarchy is not assumed to be known. The effects of external constraints on 13 from Daya Bay are shown. NuFact 8/22/13

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