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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

  10. New International Underground Science Facility At the Sudbury site: SNOLAB • - Underground Laboratory (2 km deep) ($ 38M) funded: Complete end-2007 • Surface Laboratory ($ 10 M) funded: Complete September, 2005 • Cryopit addition underground: Funding support nearly completed ($ 14 M) • Excavation to be completed in early 2008 • (Cavity capable of housing 100 tons of liquid cryogen, with an independent path for venting gas to the surface in case of accident.) • Total additional excavated volume in new lab: 2 times SNO volume. • To pursue Experiments that benefit from a very deep and clean lab: • Direct Observation of Dark Matter (WIMPS) via nuclear recoil • Neutrino-less Double Beta Decay • Low Energy Solar Neutrinos • Particle physics and solar physics • Geo – neutrinos • Supernova Neutrinos • Reactor Neutrinos

  11. To Be Ready for Experiments: 2008 The New SNOLAB New Excavation To Date Cryopit 2/3 40 to 400 times lower m fluxes than Gran Sasso, Kamioka. SNO All Lab Air: Class < 2000

  12. Total Muon Flux vs Depth Relative to Flat Overburden Canfranc 2.5 km.w.e. Frejus 4.8 km.w.e. D. Mei, A. Hime astro-ph/0512125

  13. Surface Facilities Control Rooms Clean Room Laboratories Meeting Rooms

  14. Letters of Interest for SNOLAB Dark Matter: Timing of Liquid Argon/Neon Scintillation: DEAP/CLEAN (1 Tonne) Freon Super-saturated Gel: PICASSO Silicon Bolometers: SUPER-CDMS Liquid Xe: ZEPLIN- III, LUX (1 Tonne) Gaseous Xe: DRIFT Neutrino-less Double Beta Decay: 150Nd: Organo-metallic in liquid scintillator in SNO+ 76Ge: MAJORANA or next generation GERDA/MAJORANA 136Xe: EXO (Gas or Liquid) CdTe: COBRA Solar Neutrinos: Liquid Scintillator: SNO+ (also Reactor Neutrinos, Geo-neutrinos) Liquid Ne: CLEAN (also Dark Matter) SuperNovae: HALO: Pb plus SNO 3He detectors; SNO+ 5 th Workshop and Experiment Review Committee Aug 21, 22, 2006 www.snolab.ca

  15. SNO+ 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 Replace Heavy water with 1000 tonnes Liquid Scintillator

  16. Best Scintillator Identified • Linear Alkyl Benzene (LAB) has the smallest scattering of all scintillating solvents investigated and the best acrylic compatibility. • density r = 0.86 g/cm3: Ropes to hold down acrylic vessel. • …default is Petresa LAB with 4 g/L PPO, wavelength shifter 10-50 mg/L bisMSB • because LAB solvent is undiluted and SNO photocathode coverage is high,expect light output (photoelectrons/MeV) ~3× KamLAND • Nd metallic-organic compound has been demonstrated to have long attenuation lengths, stable for more than a year. • 0.1 % of Nd can be added with little degradation of light output.

  17. Neutrino-less Double Beta Decay Candidate 150Nd table from F. Avignone Neutrino 2004 • 3.37 MeV endpoint • (9.7 ± 0.7 ± 1.0) × 1018 yr 2nbb half-life (NEMO-III) • isotopic abundance 5.6% (in SNO+ 0.1% loading=56 kg) • Nd is one of the most favorable double beta decay candidates with large phase space due to high endpoint.

  18. SNO+ (150Nd Neutrino-less Double Beta Decay) 0n: 1057 events per year with 500 kg 150Nd-loaded liquid scintillator in SNO+. Simulation assuming light output and background similar to Kamland. One year of data mn = 0.15 eV U Chain Th Chain Super-Nemo and SNO+ seek use of Laser Isotope Separation facility in France to enrich 100’s of kg of 150Nd isotope. CEA has agreed to initial study during 07/08

  19. NC non-standard Lagrangian pep solar n • SNO+ (Liquid Scintillator) • Test the MSW Energy Dependence, transition from MSW (8B) to vacuum osc. (pp). • Look for: - Non-standard interactions - Mass-varying neutrinos Barger, Huber, Marfatia, hep-ph/0502196 Friedland, Lunardini, Peña-Garay, hep-ph/0402266 Miranda, Tórtola, Valle, hep-ph/0406280 The pep solar neutrinos are at a sensitive energy to test for new physics. The pep(and CNO) can be observed at SNO+ depth with no 11C interference.

  20. 3 Years of Data CNO pep Assuming U, Th as achieved at Kamland, Bi, K set at Kamland objectives, Max Likelihood fit extracts pep at +- 4%. Negligible background from 11C at this depth.

  21. Other Double Beta DecayExample: Majorana • 60 to 120 kg enriched 86% 76Ge • many crystals, each segmented • advanced signal processing • require special low background materials • deep, clean underground location • Few keV resolution at Q = 2039 keV • known technology • sensitivity to few 1027 years • mn <~ 0.1 eV US, Canada, Japan, Russia collaboration • MOU for future consideration of >~ 500 kg experiment with GERDA

  22. EXO: Liquid or Gas (~ 200 kg enriched 136Xe at present) • EXO-200 Liquid Detector with scintillation and ionization measurement: • To Be Deployed at WIPP in June 2007. (No Ba tagging) • Independent development of Laser-tagging of single Barium atoms in liquid. • EXO-Gas: Wire chamber under development in parallel • Future – much larger mass. (Carleton, Laurentian, SNOLAB, TRIUMF development work) EXO-200: Expected sensitivity < 0.35 eV Liquid Compact detector No pressure vessel Small shield -> lower purity reqd. Gas Energy resolution s < 0.6% Tracking & multi-site rejection In-situ Ba tagging Large Cryostat Poorer energy, tracking resolution Ex-situ Ba tagging Large detector Needs very large shield Pressure vessel is massive

  23. 108 simulated e-’s 100 simulated WIMPs From simulation, g rejection > 108 @ 10 keV DARK MATTER DEAP/CLEAN: 1 Tonne Fiducial Liquid Argon • - Scintillation time spectrum for Ar • enables WIMP recoils to be • separated from gammas from • 39Ar background. • Simulation indicates that 39Ar • and other gamma-beta • backgrounds can be discriminated • from WIMPS using only scintillation • light for up to 1 tonne fiducial • Volume of liquid argon. • - DEAP and CLEAN collaborations • have come together to build this • new detector with a simple and easily • scaled technology at SNOLAB. M.G. Boulay & A. Hime, astro-ph/0411358

  24. Discrimination in liquid argon from DEAP-0 (<1 kg) O(1in 105) consistent with room neutrons in surface lab. <pe> = 60 DEAP- 1 (7 kg) Is in operation on surface. To be sited in SNOLAB in May 2007. Will test Discrimination to 109 <pe> = 60 corresponds to 10 keV threshold with 75% coverage

  25. DEAP/CLEAN Detector • - 3.5 Tonnes of pure liquid Argon (Neon) in an 85-cm spherical acrylic vessel, viewed by 200 cold PMT’s through acrylic light guides. Very high light collection, external H2O shield. • - Objective: 1 tonne liquid central fiducial volume to eliminate surface radioactivity and obtain sensitivity to WIMP cross sections down to 10- 46 cm2. (1000 times better than present limits for spin-independent cross section). • SNOLAB depth removes neutrons from cosmic rays. Residual backgrounds are only few per year. • Argon with reduced 39Ar is also under investigation. • - $ 3 M of $ 5 M total funding available soon. • - Planned deployment during 2009, operation in 2010.

  26. For Example: Muon-induced Neutron Background for a CDMS-type Dark Matter Experiment: Mei and Hime: astro-ph/0512125

  27. Spin Independent Interaction } Where we Are Minimal Super- Symmetric Models Super-CDMS LUX } Future Expts. 10-46cm2 DEAP/CLEAN

  28. Cryogenic Dark Matter Search: CDMS

  29. Planned start of construction: 2008 assuming funding approval soon.

  30. ZEPLIN-III 8 kg Xe Liquid – gas Scintillation + Electroluminescence Ready for Immediate Deployment

  31. WIMP-Nucleus Spin-Dependent Interaction Fluorine is very sensitive for the spin-dependent interaction Montreal, Queen’s Indiana, Pisa, BTI

  32. SPIN - DEPENDENT INTERACTION 20 g: hep-ex/0502028 PICASSO 1 kg 2 kg being run in 2006-07 10 kg 100 kg

  33. Initial Suite of Experiments Cryopit: 1 of 2008: DEAP/CLEAN 2009: LUX Future??:Large EXO, CLEAN, 1-ton GERDA/MAJORANA Cube Hall:1 (or 2) of 2008: DEAP/CLEAN 2009: PICASSO-III 2009: LUX (1 ton Xe) 2008:HALO SNO Utility Rm: Now: PICASSO-IB (2kg) Ladder Labs: 2 of 2008: Super-CDMS 2009: PICASSO IIB 2009: EXO-200-Gas 2009: Majorana (TBD) South Drift: 2008: ZEPLIN-III SNO Control Rm: 2007: DEAP-1 SNO Cavern: 2008: SNO+

  34. Summary • SNO is analyzing data from its three phases and will be providing new publications in the near future with improved accuracy. • Underground measurements have opened new areas of investigation for physics beyond the Standard Model of Elementary Particles and astrophysical topics. • With a very deep, clean international underground facility (SNOLAB) we have an exciting future for sensitive measurements of solar neutrinos, neutrino-less double beta decay and dark matter particles.

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