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Telescopes: SNO and the New SNOLAB

Telescopes: SNO and the New SNOLAB. 2 km underground in Vale-INCO’s Creighton Mine near Sudbury, Ontario. Neutrino Telescopes Venice March 10, 2009 (Galileo + 400). Art McDonald Queen’s University, Kingston For the SNO Collaboration. The Sudbury Neutrino Observatory: SNO.

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Telescopes: SNO and the New SNOLAB

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  1. Telescopes: SNO and the New SNOLAB 2 km underground in Vale-INCO’s Creighton Mine near Sudbury, Ontario Neutrino Telescopes Venice March 10, 2009 (Galileo + 400) Art McDonald Queen’s University, Kingston For the SNO Collaboration

  2. The Sudbury Neutrino Observatory: SNO 6800 feet (~2km) underground Acrylic vessel (AV) 12 m diameter 1000 tonnes D2O ($300 million) 1700 tonnes H2O inner shielding Creighton mine Sudbury, CA 5300 tonnes H2O outer shielding - Entire detector Built as a Class 2000 Clean room - Low Radioactivity Detector materials ~9500 PMT’s The heavy water has been returned and development work is in progress on SNO+ with liquid scintillator and 150Nd additive.

  3. , SNO Bahcall et al. SNO: Solving the “Solar Neutrino Problem” Previous Experiments Sensitive Mainly to Electron Neutrinos Solar Model Flux Calculations CNO SNO was designed to observe separately ne and all neutrino types to determine if low ne fluxes come from solar models or neutrino flavor change (New Physics)

  4. 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)(D2O & H2O) x+e- x+e- x, but enhanced fore Events point away from the sun.

  5. 35Cl+n 2H+n 8.6 MeV 6.25 MeV 3H 36Cl SNO: 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-Dec. 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

  6. If neutrinos have mass: As of today: Oscillation of 3 massive active neutrinos is clearly the dominant effect: For 3 Active neutrinos. (MiniBoone has recently ruled out LSND result) Maki-Nakagawa-Sakata-Pontecorvo matrix ? (Double b decay only) ? ? Solar,Reactor Atmospheric CP Violating Phase Reactor, Accel. Majorana Phases Range defined for Dm12, Dm23 For two neutrino oscillation in a vacuum: (a valid approximation in many cases) Leptogenesis: d or a phases -> possible matter/antimatter asymmetry in Early Universe

  7. Matter Effects – the MSW effect (Mikheyev, Smirnov, Wolfenstein) The extra term arises because solarne have an extra interaction via W exchange with electrons in the Sun or Earth. In the oscillation formula: MSW effect can produce an energy spectrum distortion and flavor regeneration in Earth giving a Day-night effect. If observed, matter interactions define the mass heirarchy.

  8. The solar results are best fit with the MSW effect and define the mass hierarchy • (m2 > m1) through the Matter interaction. • SNO: CC/NC flux defines • tan2q12< 1 (ie Non - Maximal mixing) by more than 5 standard deviations Reactor Anti- Neutrinos (KAMLAND) Solar Neutrinos (SNO plus others) The Total Flux of Active Neutrinos agrees reasonably well with solar models: 5.95 (1+- 0.11) [BPS08 (GS)] 4.72 (1+- 0.11) [BPS08 (AGS)] However, metal abundances, mixing …? -> CNO measurements: Haxton, Serenelli SNO Results for Salt Phase Electron Neutrinos are only 1/3 of Total Flavor change determined by > 7 s.

  9. Final Phase: SNO Phase III Neutral-Current Detectors (NCD): An array of 3He proportional counters:40 strings on 1-m grid: ~440 m Phase III production data taking Dec 2004 to Dec 2006. D2O and NCD’s now removed. NCD’s to be used in HALO: a lead-based Supernova detector for ne • Improve solar neutrino flux by breaking the CC and NC correlation: • CC: Cherenkov Signal PMT Array • NC: n+3He  NCD Array • Improvement in 12, as

  10. Neutrons from solar neutrino interactions NC Signal: 983 ± 77 Neutron background: 185 ± 25 Alphas and Instrumentals: 6126 ± 250 (0.4 to 1.4 MeV) ~ 1 alpha background event per month per meter of detector. SNO PAPER: arXiv:0806.0989v3 [nucl-ex] Phys.Rev.Lett.101:111301,2008

  11. NCD Simulation Results data Pulse Width (ns) full model of detector physics to simulate pulse shape characteristics, correlations tuned on calibration data MC Energy (MeV) Pulse Width (ns) neutron signal alpha backgrounds: surface polonium decay bulk U and Th decay wire polonium decay wire bulk decay insulator polonium decay insulator bulk U and Th decay Energy (MeV)

  12. stat stat + syst SNO Fluxes: 3 Phases p-value for consistency of NC/CC/ES in the salt & NCD phases + D2O NC(unconstr) is 32.8%

  13. Solar + KamLAND fit results • This work: • SNO NCD results agree well with previous SNO phases. Minimal correlation with CC. Different systematics. • New precision on  • Future solar analysis: • LETA (Low Energy Threshold Analysis) • 3-neutrino analysis • hep flux • Day-night, other variations • Muons, atmospheric  eV2 degrees deg (previous) Neutrino flavour symmetry phenomenology: (Smirnov summary at Neutrino 2008) Tri-Bi-Maximal Mixing: 35.2 deg Quark-Lepton Complementarity: 32.2 deg (q12 + qCabbibo = 45 deg) The accuracy on q12 and f8B will improve with new data analysis: SNO LETA

  14. SNO Physics (Telescope) Program • Solar Neutrinos (7 papers to date) • Electron Neutrino Flux • Total Neutrino Flux • Electron Neutrino Energy Spectrum Distortion • Day/Night effects • hep neutrinos hep-ex 0607010 • Periodic variations:[Variations < 8% (1 dy to 10 yrs)] hep-ex/0507079 • Atmospheric Neutrinos & Muons (arXiv: hep-ex 0902.2776) • Downward going cosmic muon flux • Atmospheric neutrinos: wide angular dependence [Look above horizon] • Supernova Watch (SNEWS) • Limit for Solar Electron Antineutrinos hep-ex/0407029 • Nucleon decay (“Invisible” Modes: N nnn) Phys.Rev.Lett. 92 (2004) [Improves limit by 1000] • Supernova Relic Electron Neutrinos hep-ex 0607010

  15. SNO Muon & Atmospheric Neutrino Analysis Through-going muons SNO X Super-K SNO provides a test of the Super-Kamiokande oscillation parameters (Dm2 = 2.1 x 10-3 ev2, sin22Q = 1.00 +- 0.032). SNO: 2.6 x 10-3 ev2 SNO also provides a measure of the cosmic neutrino flux above the horizon. Normalization of Bartol 3-D atmospheric neutrino flux model: 1.22 +- 0.10.

  16. Downward-going Muons SNO data for downward-going muons extends the previous data to about 13.5 km of water equivalent, where atmospheric neutrino generated muons begin to contribute significantly. Also studying neutron production From muons. New SNO paper arXiv: hep-ex 0902.2776

  17. SNO+ : Liquid Scintillator with Nd for Double Beta Decay + Solar, geo - n The organic liquid is lighter than water so the Acrylic Vessel must be held down. New scintillator purification systems are required. 1000 tonnes of liquid scintillator (LAB) (plus 1 tonne of natural Nd = 56 kg of 150Nd for Double Beta Decay) Existing AV Support Ropes New AV Hold Down Ropes Otherwise, the existing detector, electronics etc. are unchanged.

  18. SNO+: Neutrino-less Double Beta Decay: 150Nd • Nd is one of the most favorable double beta decay candidates with large phase space due to high endpoint: 3.37 MeV. • Ideal scintillator (Linear Alkyl Benzene) has been identified. More light output than Kamland, Borexino, no effect on acrylic. • Nd metallic-organic compound has been demonstrated to have long attenuation lengths, stable for more than 2 years. • 1 tonne of Nd will cause very little degradation of light output. (Successful test in 2008 with small chamber in center of SNO) • Isotopic abundance 5.6% (in SNO+ 1 tonne Nd = 56 kg 150Nd) • Possible enrichment of 150Nd or increase in the amount of natural Nd. • SNO+ Capital proposal submitted, decision June 2009. • Plan to start with natural Nd in 2011. • Other physics: CNO solar neutrinos, pep solar neutrinos to study neutrino properties, geo-neutrinos, supernova search. (No 11C background at this depth.) Queen’s, Alberta, Laurentian, SNOLAB, BNL, Washington, Penn, Texas, LIP Lisbon, Idaho State, Idaho Nat Lab, Oxford, Sussex, TUDresden, Leeds,UCLondon

  19. Capability for 3 Years of Data Solar Neutrinos CNO pep Backgrounds assumed at Kamland observed values plus their purification objectives for 210Bi, 40K. Negligible background from 11C at SNOLAB depth.

  20. mnbb (eV) Lightest neutrino (m1) in eV Measuring Effective n Mass mnbb= |iUei ²mi | mnbb= |m1 cos2q13cos²12 + m2 e2i cos2q13sin²12 + m3 e2isin²13| Mass Hierarchies Present Expts. Inverted Degenerate 0.04 eV Normal normal hierarchy inverted hierarchy Normal Inverted SNO+ Sensitivity (3 years): 0.1 eV with 1 tonne natural Nd 0.04 with 500 kg 150Nd.

  21. SNO+ (150Nd n - less Double Beta Decay) 0n: For example: 1057 events per year with 500 kg 150Nd-loaded liquid scintillator in SNO+. Simulation assuming light output and background similar to Kamland. (Borexino has done better) One year of data mn = 0.15 eV U Chain Th Chain ~Flat 8B Solar n “background” Sensitivity Limits (3 yrs): 1000 kg natural Nd (56 kg isotope): mnbb ~ 0.1 eV (start 2011) With 500 kg enriched 150Nd: mnbb ~ 0.04 eV

  22. Geo-Neutrino Signal • event rates: • KamLAND: 33 events per year (1000 tons CH2) / 142 events reactor • SNO+: 44 events per year (1000 tons CH2) / 42 events reactor • - four times smaller reactor background in the geo-neutrino region than in KamLAND • test models in a region dominated by crustal components. • very well characterized local geology enables residuals to probe the U and Th content of the deep Earth • reactor spectrum “dip” helps constrain Dm2 and q12 SNO+ geo-neutrinos and reactor background

  23. SNOLAB Construction is complete – Final cleaning occurring Letters of Intent/Interest (Red implies approval for siting) : Dark Matter: Timing of Liquid Argon/Neon Scintillation: DEAP-1 (7 kg),MINI-CLEAN (360 kg), DEAP/CLEAN (3.6 Tonne) Freon Super-saturated Gel: PICASSO Silicon Bolometers: SUPER-CDMS(25 kg) Double Beta Decay: 150Nd: In liquid scintillator in SNO+ 136Xe: EXO (Gas or Liquid) (Longer Term) CdTe: COBRA(Longer Term) Solar Neutrinos: Liquid Scintillator: SNO+ (also Reactor Neutrinos, Geo-neutrinos) SuperNovae: SNO+: Liquid scintillator; HALO: Pb plus SNO 3He detectors.

  24. New large scale project. 2009: MiniCLEAN 360 2010: DEAP/CLEAN 3600 SNOLAB Phase II Cryopit 2009: HALO Cube Hall 2010: PICASSO IIB? 2010: EXO-200-Gas? 2011: SuperCDMS ? Now:PICASSO-II Now:DEAP-1 Ladder Labs Utility Area 2010: SNO+ SNO Cavern Personnel facilities All Lab Air: Class < 2000 SNOLAB @ Neutrino 2008 Christchurch May 28th, 2008

  25. Personnel Facility

  26. Lunch Room

  27. Start of Clean conditions for the new SNOLAB: Feb. 2009 Lunch Room

  28. MiniCLEAN 360 kg 2009 DEAP/CLEAN 3.6 tonne 2010 Cube Hall Dark Matter Search with Liquid Argon: DEAP-1 (7 kg Ar) (Running); Future: Mini-Clean (360 kg Ar or Ne) and DEAP-3600 (3.6 tonnesAr) WIMP-Induced Nuclear recoils in Ar are discriminated from beta and gamma radioactivity (39Ar) by timing of the light emitted.

  29. Background suppression better than 2.6 E-8 demonstrated to date Backgrounds (g’s) Dark Matter Search at SNOLAB with Liquid Argon Yellow: Prompt light region Blue: Late light region DEAP-1 at SNOLAB For DEAP/CLEAN 3600 suppression of > 10-9 is required. Note also that sources of Ar depleted x 20 in 39Ar have been found and are being developed with the Princeton group. Signal (nuclear recoil)

  30. Super CDMS 25 kg CDMS-II: ~50 kg-days (Ge) XENON-10: ~300 kg-days (Xe) DEAP- 3600: 1,000,000 kg-days (Ar) (3 yrs)

  31. PICASSO Project In CAnada to Search for Supersymmetric Objects • detectors consist of tiny (5 to 100 m) halocarbon superheated-liquid droplets (e.g. C3F8, C4F10) embedded in a gel • WIMP-induced nuclear recoils nucleate a bubble; expanding, evaporating bubble produces an acoustic signal detected by piezo microphone 19F favourable target to search for “spin-dependent” WIMP scattering 32 detector modules containing 4 L of gel insensitive to beta and gamma radiation; some discrimination exists for alphas

  32. SPIN DEPENDENT WIMP INTERACTION: Studied with Fluorine dispersed in supersaturated gel – WIMP nuclear recoils create bubbles - detected acoustically. Low response for other radioactivity. Breakthrough this year: alpha discrimination PICASSO PHASES Phase 1a: (published in ’05 PLB, NIM) 20g 2kgd Phase Ib: (ongoing) 2.6 kg 700 kgd Bckg red. 1/6 – 1/10 Phase Ib/100: 2.6 kg 700 kgd Bckg: red. 1/100 Phase II: 25 kg 7000 kgd Larger modules 30L MSSM Theory Predictions

  33. H elium And L ead Observatory Pb: Most sensitivity to electron neutrinos. ~ 50 events for SN at center of Galaxy. A lead detector for supernova neutrinos in SNOLAB Laurentian, TRIUMF, SNOLAB, LANL, Washington, Duke, Minnesota, Digipen IT HALO-1: 80 tons of existing Pb & SNO Neutron Detector Array

  34. SUMMARY • SNO operation is complete, further papers to come over next year. • SNOLAB construction is complete, final cleanliness in progress. • Several experiments are already running in existing clean space. • A number of other experiments have been approved for siting in • the near future for neutrinos, double beta decay, Dark Matter. • Stay tuned for some exciting future physics results.

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