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SNO and the new SNOLAB

SNO and the new SNOLAB. SNO: Heavy Water Phase Complete Status of SNOLAB Future experiments at SNOLAB: (Dark Matter, Double beta, Solar n , geo- n , supernova n ). Art McDonald, SNO Institute Director For the SNO Collaboration Neutrino Telescopes, Venice, 2007.

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SNO and the new SNOLAB

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  1. SNO and the new SNOLAB • SNO: Heavy Water Phase Complete • Status of SNOLAB • Future experiments at SNOLAB: (Dark Matter, Double beta, Solar n, geo-n, supernova n) Art McDonald, SNO Institute Director For the SNO Collaboration Neutrino Telescopes, Venice, 2007

  2. Unique Signatures in SNO (D2O) Charged-Current (CC) e+d  e-+p+p Ethresh = 1.4 MeV eonly Neutral-Current (NC) x+d x+n+p Ethresh = 2.2 MeV Equally sensitive to e nmt 3 ways to detect neutrons Elastic Scattering (ES) x+e- x+e- x, but enhanced fore

  3. 35Cl+n 2H+n 8.6 MeV 6.25 MeV 3H 36Cl 3 neutron (NC) detectionmethods (systematically different) Phase I (D2O) Nov. 99 - May 01 Phase II (salt) July 01 - Sep. 03 Phase III (3He) Nov. 04 - Nov. 06 n captures on 2H(n, g)3H Effc. ~14.4% NC and CC separation by energy, radial, and directional distributions 2 t NaCl. n captures on 35Cl(n, g)36Cl Effc. ~40% NC and CC separation by event isotropy 40 proportional counters 3He(n, p)3H Effc. ~ 30% capture Measure NC rate with entirely different detection system. 5 cm n 3H p 3He n + 3He  p + 3H

  4. Sudbury Neutrino Observatory Support Structure for 9500 PMTs, 60% coverage 12 m Diameter Acrylic Vessel 1700 tonnes Inner Shielding H2O 5300 tonnes Outer Shield H2O Urylon Liner and Radon Seal 200 tonnes has been returned 1000 tonnes D2O ($300 M)

  5. SALT PHASE (“Near Background-free” analysis) EVENTS VS VOLUME: Bkg < 10% ISOTROPY: NC, CC separation Heavy water DIRECTION FROM SUN ENERGY SPECTRUM FROM CC REACTION

  6. Flavor change determined by > 7 s. CC, NC FLUXES MEASURED INDEPENDENTLY nm , nt The Total Flux of Active Neutrinos is measured independently (NC) and agrees well with solar model Calculations: 4.7 +- 0.5 (BPS07), 5.31 +- 0.6 (Turck-Chieze et al 04) Electron neutrinos High accuracy for q12. Implies Matter Interactions (Folgi, Lisi 2004)

  7. SOLAR ONLY AFTER NEW SNO SALT DATA • - SNO: CC/NC flux • defines tan2q12< 1 • (ie Non - Maximal mixing) • by more than 5 • standard deviations. • The mass hierarchy is • defined (m2 > m1) • through the • matter interaction (MSW) Large mixing Angle (LMA) Region: MSW LMA for solar n predicts very small spectral distortion, small (~ 3 %) day-night asymmetry, as observed by SNO, SK SOLAR PLUS KAMLAND (assuming CPT) (Reactor n’s)

  8. Total Radioactivity similar To Phase I, II Final Phase: SNO Phase III Neutral-Current Detectors (NCD): An array of 3He proportional counters 40 strings on 1-m grid ~440 m total active length • Search for spectral distortion • Improve solar neutrino flux by breaking the CC and NC correlation ( = -0.53 in Phase II): • CC: Cherenkov Signal PMT Array • NC: n+3He  NCD Array • Improvement in 12, as Blind Analysis Phase III production data taking began Dec 2004; completed November 2006

  9. Another analysis is almost complete that combines data from the first two SNO Phases and reduces the threshold by ~ 1 MeV. This also provides improved accuracy on CC/NC flux ratio. BLIND ANALYSIS: Add in unknown number of neutrons from muons

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