SNO and the new SNOLAB
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SNO and the new SNOLAB • SNO: Heavy Water Phase Complete • Status of SNOLAB • Future experiments at SNOLAB: (Dark Matter, Double beta, Solar , geo-, supernova ) Art McDonald, SNO Institute Director For the SNO Collaboration Neutrino Telescopes, Venice, 2007
description
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. - PowerPoint PPT Presentation
Transcript of 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 , geo-, supernova )
Art McDonald, SNO Institute Director
For the SNO CollaborationNeutrino Telescopes, Venice, 2007
Unique Signatures in SNO (D2O)Charged-Current (CC)e+d e-+p+pEthresh = 1.4 MeVee onlyonly
Elastic Scattering (ES)x+e- x+e-
x, but enhanced for e
Neutral-Current (NC) x+d x+n+p Ethresh = 2.2 MeV
Equally sensitive to Equally sensitive to e e
3 ways todetect neutrons
Phase II (salt)July 01 - Sep. 03
Phase III (3He)Nov. 04 - Nov. 06
Phase I (D2O)Nov. 99 - May 01
3 neutron (NC) detectionmethods (systematically different)
n captures on2H(n, )3H
Effc. ~14.4% NC and CC separation by energy, radial, and
directional distributions
40 proportional counters
3He(n, p)3HEffc. ~ 30% capture
Measure NC rate with entirely different
detection system.
2 t NaCl. n captures on35Cl(n, )36ClEffc. ~40%
NC and CC separation by event isotropy
36Cl
35Cl+n 8.6 MeV
3H
2H+n 6.25 MeV
n + 3He p + 3H
p3H
5 cm
n
3He
Sudbury Neutrino Observatory
1700 tonnes InnerShielding H2O
1000 tonnes D2O ($300 M)
5300 tonnes Outer Shield H2O
12 m Diameter Acrylic Vessel
Support Structure for 9500 PMTs, 60% coverage
Urylon Liner andRadon Seal
200 tonnes has been returned
ISOTROPY: NC, CC separation
DIRECTION FROM SUN
EVENTS VS VOLUME: Bkg < 10%
ENERGY SPECTRUM FROM CC REACTIONHeavy water
SALT PHASE (“Near Background-free” analysis)
)syst.()stat.( 35.2
)syst.()stat.( 94.4
)syst.()stat.( 68.1
15.015.0
22.022.0
38.034.0
21.021.0
08.009.0
06.006.0
ES
NC
CC
)scm10 of units(In 126
122029.0
031.0 sin)stat.(023.034.0
NC
CCeeP
High accuracy for
Electron neutrinos
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)
CC, NC FLUXESMEASURED
INDEPENDENTLY
Flavor change determined by > 7
)1.3(45.0 eeP Implies Matter Interactions (Folgi, Lisi 2004)
- SNO: CC/NC fluxdefines tan2 < 1 (ie Non - Maximal mixing)by more than 5standard deviations.
-The mass hierarchy isdefined (m2 > m1) through thematter interaction (MSW)
SOLAR ONLY
AFTER NEW
SNO SALT
DATA
SOLAR PLUS KAMLAND
(assuming CPT)
(Reactor ’s)
Large mixing
Angle (LMA)
Region: MSW
LMA for solar predicts very small
spectral distortion, small (~ 3 %) day-night
asymmetry, as observed by SNO, SK
Final Phase: SNO Phase III
• 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
Neutral-Current Detectors (NCD): An array of 3He proportional counters
40 strings on 1-m grid~440 m total active length
Phase III production data taking began Dec 2004; completed November 2006
Correlations D2O unconstrained D2O constrained Salt unconstrained NCD
NC,CC -0.950 -0.520 -0.521 ~0
CC,ES -0.208 -0.162 -0.156 ~-0.2
ES,NC -0.297 -0.105 -0.064 ~0
Blind Analysis
Total Radioactivity similarTo Phase I, II
Another analysis is almost complete that combines data fromthe 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
New International Underground Science FacilityAt 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
The New SNOLAB
SNO
To Be Ready for Experiments: 2008
40 to 400 times lower fluxes than Gran Sasso, Kamioka.
NewExcavation
To Date
2/3
All Lab Air: Class < 2000
Cryopit
Total Muon Flux vs Depth Relative to Flat Overburden
D. Mei, A. Hime astro-ph/0512125
Canfranc 2.5 km.w.e.
Frejus 4.8 km.w.e.
Control Rooms
Meeting Rooms Clean Room Laboratories
Surface Facilities
Letters of Interest for SNOLABDark 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, 2006www.snolab.ca
SNO+
1700 tonnes InnerShielding H2O
Replace Heavy water with 1000 tonnes Liquid Scintillator
5300 tonnes Outer Shield H2O
12 m Diameter Acrylic Vessel
Support Structure for 9500 PMTs, 60% coverage
Urylon Liner andRadon Seal
Best Scintillator Identified
• Linear Alkyl Benzene (LAB) has the smallest scattering of all scintillating solvents investigated and the best acrylic compatibility.
• density = 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.
150Nd 3.37 MeV endpoint (9.7 ± 0.7 ± 1.0) × 1018 yr
2half-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.
table from F. Avignone Neutrino 2004
57 780.73
35(phase space) 2(nuclear calculation)
Neutrino-less Double Beta Decay Candidate
0: 1057 events peryear with 500 kg150Nd-loaded liquidscintillator in SNO+.
Simulationassuming lightoutput and backgroundsimilar to Kamland.
SNO+ (150Nd Neutrino-less Double Beta Decay)
One year of datam= 0.15 eV
Super-Nemo and SNO+ seek use of Laser Isotope Separation facility in Franceto enrich 100’s of kg of 150Nd isotope. CEA has agreed to initial study during 07/08
U ChainTh Chain
• Test the MSW EnergyDependence, transition from MSW (8B) to vacuum osc. (pp).• Look for: - Non-standard interactions - Mass-varying neutrinos
Friedland, Lunardini, Peña-Garay, hep-ph/0402266
Barger, Huber, Marfatia, hep-ph/0502196
The pep solar neutrinos are at a sensitiveenergy to test for new physics.The pep (and CNO) can be observed atSNO+ depth with no 11C interference.
pep solar NC non-standard Lagrangian
Miranda, Tórtola, Valle, hep-ph/0406280
• SNO+ (Liquid Scintillator)
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.
3 Years of Data
pep
CNO
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 m <~ 0.1 eV
US, Canada, Japan, Russia collaboration
• MOU for future consideration of >~ 500 kg experiment with GERDA
EXO: Liquid or Gas (~ 200 kg enriched 136Xe at present)
Liquid
Compact detectorNo pressure vesselSmall shield -> lower purity reqd.
Gas
Energy resolution Tracking & multi-site rejectionIn-situ Ba tagging
Large CryostatPoorer energy, tracking resolutionEx-situ Ba tagging
Large detector
Needs very large shield
Pressure vessel is massive
(Carleton, Laurentian, SNOLAB, TRIUMF development work)EXO-200: Expected sensitivity < 0.35 eV
• 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.
DEAP/CLEAN: 1 Tonne Fiducial Liquid Argon
From simulation, rejection > 108
@ 10 keV
108 simulated e-’s
100 simulatedWIMPs
M.G. Boulay & A. Hime, astro-ph/0411358
DARK MATTER
- Scintillation time spectrum for Arenables WIMP recoils to beseparated from gammas from39Ar background.
- Simulation indicates that 39Arand other gamma-beta backgrounds can be discriminatedfrom WIMPS using only scintillationlight for up to 1 tonne fiducial Volume of liquid argon.
- DEAP and CLEAN collaborationshave come together to build thisnew detector with a simple and easily scaled technology at SNOLAB.
Discrimination in liquid argon from DEAP-0 (<1 kg)
O(1in 105) consistentwith room neutrons insurface lab.
<pe> = 60 corresponds to 10 keV threshold with 75% coverage
<pe> = 60
DEAP- 1 (7 kg)Is in operation
on surface. To besited in SNOLAB
in May 2007.
Will test Discrimination
to 109
- 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.
DEAP/CLEAN Detector
For Example: Muon-induced Neutron Background for a CDMS-typeDark Matter Experiment: Mei and Hime: astro-ph/0512125
Spin Independent Interaction
} Where we Are
} Future Expts.
Minimal Super-
Symmetric Models
DEAP/CLEAN
Super-CDMSLUX
10-46cm2
Cryogenic Dark Matter Search: CDMS
Planned start of construction: 2008 assuming funding approval soon.
ZEPLIN-III
8 kg Xe Liquid – gasScintillation + ElectroluminescenceReady for Immediate Deployment
Montreal, Queen’s
Indiana, Pisa, BTI
Fluorine is very sensitive for the spin-dependent interaction
WIMP-Nucleus Spin-Dependent Interaction
SPIN - DEPENDENT
INTERACTION
1 kg
10 kg
100 kg
20 g: hep-ex/0502028
2 kg being run in 2006-07
PICASSO
SNO Cavern:2008: SNO+
SNO Utility Rm:Now: PICASSO-IB (2kg)
Ladder Labs: 2 of2008: Super-CDMS2009: PICASSO IIB2009: EXO-200-Gas2009: Majorana (TBD)
SNO Control Rm:2007: DEAP-1
South Drift:2008: ZEPLIN-III
Cube Hall:1 (or 2) of2008: DEAP/CLEAN2009: PICASSO-III2009: LUX (1 ton Xe)
Cryopit: 1 of2008: DEAP/CLEAN2009: LUXFuture??:Large EXO,CLEAN, 1-ton GERDA/MAJORANA
2008:HALO
Initial Suite of Experiments
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.
