1 / 35

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.

gen
Télécharger la présentation

SNO and the new SNOLAB

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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.

More Related