telescopes: sno and the new snolab art mcdonald queen’s university, kingston for the sno...
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Telescopes: SNO and the New SNOLAB
Art McDonaldQueen’s University, Kingston
For the SNO Collaboration
2 km underground in Vale-INCO’s CreightonMine near Sudbury, Ontario
Neutrino TelescopesVenice
March 10, 2009(Galileo + 400)
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Acrylic vessel (AV) 12 m diameter
1700 tonnes H2O inner shielding
1000 tonnes D2O($300 million)
5300 tonnes H2O outer shielding
~9500 PMT’s
Creighton mineSudbury, CA
The Sudbury Neutrino Observatory: SNO6800 feet (~2km) underground
The heavy water has been returned and development work is in progress on SNO+ with liquid scintillator and 150Nd additive.
- Entire detectorBuilt as a Class 2000
Clean room- Low RadioactivityDetector materials
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Bahcall et al.
, SNO
SNO: Solving the “Solar Neutrino Problem”Solar Model Flux Calculations
CNO
SNO was designed to observe separately e and all neutrino types to determine if low e fluxes come from solar models or neutrino flavor change (New Physics)
Previous Experiments Sensitive Mainly to Electron Neutrinos
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Unique Signatures in SNO (D2O)
Charged-Current (CC)e+d e-+p+pEthresh = 1.4 MeV
ee onlyonly
Elastic Scattering (ES) (D2O & H2O)x+e- x+e-
x, but enhanced for e Events point away from the sun.
Neutral-Current (NC) x+d x+n+p Ethresh = 2.2 MeV
Equally sensitive to Equally sensitive to e e
3 ways todetect neutrons
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Phase II (salt)July 01 - Sep. 03
Phase III (3He)Nov. 04-Dec. 06
Phase I (D2O)Nov. 99 - May 01
SNO: 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
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ijijijij
ii
i
τττ
μμμ
eee
li
sandcwhere
e
e
cs
sc
iδecs
sccs
sc
UUU
UUU
UUU
U
sin,cos
00
00
001
0
010
0
00
010
001
0
0
001
100
0
0
2/
2/
1313
1313
2323
23231212
1212
321
321
321
3
2
ilil U If neutrinos have mass:
)E
LΔm.(θ)νP(ν eμ
222 271sin2sin
For 3 Active neutrinos. (MiniBoone has recently ruled out LSND result)
Solar,Reactor Atmospheric
As of today: Oscillation of 3 massive active neutrinos is clearly the dominant effect:
For two neutrino oscillation in a vacuum: (a valid approximation in many cases)
CP Violating Phase Reactor, Accel. Majorana Phases
Range defined for m12, m23
Maki-Nakagawa-Sakata-Pontecorvo matrix
(Double decay only)?
??
Leptogenesis: or phases -> possible matter/antimatter asymmetry in Early Universe
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Matter Effects – the MSW effect
x
e
x
e Hdt
di
cos2θ
4E
Δmsin2θ
4E
Δm
sin2θ4E
ΔmNG2cos2θ
4E
Δm
H 22
2
eF
2
2
22
22
/2
2sin)2cos(
2sin2sin
mENG eF
m
The extra term arises because solar e have an extra interaction via W exchange with electrons in the Sun or Earth.
In the oscillation formula:
(Mikheyev, Smirnov, Wolfenstein)
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.
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)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
029.0031.0)stat.(023.034.0
NC
CC
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
Flavor change determined by > 7
Electron Neutrinos are only 1/3 of Total
-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 tan2 < 1 (ie Non - Maximal mixing) by more than 5 standard deviations
SolarNeutrinos(SNO plus others)
Reactor Anti-Neutrinos(KAMLAND)
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Final Phase: SNO Phase III
• 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
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 e
122sin
NC
CC
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Neutrons from solar neutrino interactions
NC Signal:983 ± 77
Neutron background:185 ± 25
Alphas and Instrumentals:6126 ± 250(0.4 to 1.4 MeV)
SNO PAPER: arXiv:0806.0989v3 [nucl-ex] Phys.Rev.Lett.101:111301,2008
~ 1 alpha background event per month per meter of detector.
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NCD Simulation Results data
MC Energy (MeV)
Energy (MeV)
Puls
e W
idth
(nns)
Puls
e W
idth
(nns)
full model of detector physicsto simulate pulse shape
characteristics, correlations
tuned on calibration data
neutron signal
alpha backgrounds:surface polonium decaybulk U and Th decay wire polonium decaywire bulk decayinsulator polonium decayinsulator bulk U and Th decay
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stat stat + systSNO Fluxes: 3 Phases
p-value for consistency of NC/CC/ES in the salt & NCD phases + D2O NC(unconstr) is 32.8%
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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
Solar + KamLAND fit results
519.021.0
2 1059.7 m eV2
degrees3.12.112 4.34
%)7~(1091.4 126
8 scmB
4.22.212 9.33
deg (previous)
Neutrino flavour symmetry phenomenology: (Smirnov summary at Neutrino 2008)Tri-Bi-Maximal Mixing: 35.2 degQuark-Lepton Complementarity: 32.2 deg(12 + Cabbibo = 45 deg)
The accuracy on and 8B will improve with new data analysis: SNO LETA
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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 ) Phys.Rev.Lett. 92 (2004) [Improves limit by 1000] Supernova Relic Electron Neutrinos hep-ex 0607010
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X
SNO
Super-K
SNO provides a test of the Super-Kamiokande oscillation parameters (m2 = 2.1 x 10-3 ev2, sin22 = 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.
SNO Muon & Atmospheric Neutrino Analysis
Through-going muons
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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 productionFrom muons.
New SNO paper arXiv: hep-ex 0902.2776
Downward-going Muons
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New AV Hold Down Ropes
ExistingAV SupportRopes
The organicliquid is lighterthan water sothe Acrylic Vesselmust be held down.
New scintillator purification systems are required.
SNO+ : Liquid Scintillator with Nd for Double Beta Decay + Solar, geo -
Otherwise, the existing detector, electronics etc. are unchanged.
1000 tonnes of liquid scintillator (LAB)
(plus 1 tonne of natural Nd = 56 kg of 150Nd for Double BetaDecay)
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• 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.)
SNO+: Neutrino-less Double Beta Decay: 150Nd
Queen’s, Alberta, Laurentian, SNOLAB, BNL, Washington, Penn, Texas, LIP Lisbon, Idaho State, Idaho Nat Lab, Oxford, Sussex, TUDresden, Leeds,UCLondon
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Backgrounds assumed at Kamland observed values plus their purificationobjectives for 210Bi, 40K. Negligible background from 11C at SNOLAB depth.
Capability for 3 Years of Data
pep
CNO
Solar Neutrinos
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m
(
eV)
Lightest neutrino (m1) in eV
m = |i Uei ² mi |
m = |m1 cos213cos²12 + m2 e2i cos213sin²12 + m3 e2i sin²13|
Measuring Effective Mass
normal hierarchy inverted hierarchy
SNO+ Sensitivity (3 years): 0.1 eV with 1 tonne natural Nd0.04 with 500 kg 150Nd.
Inverted
Normal
Present Expts.
0.04 eV
Mass Hierarchies
Normal Inverted
Degenerate
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0: For example: 1057 events per year with 500 kg 150Nd-loaded liquid scintillator in SNO+.
Simulationassuming lightoutput and backgroundsimilar to Kamland.(Borexino has done better)
SNO+ (150Nd - less Double Beta Decay)
One year of datam= 0.15 eV
Sensitivity Limits (3 yrs): 1000 kg natural Nd (56 kg isotope): m ~ 0.1 eV (start 2011)With 500 kg enriched 150Nd: m ~ 0.04 eV
U ChainTh Chain
~Flat 8B Solar “background”
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event rates:• KamLAND: 33 events per year (1000 tons CH2) / 142 events reactor• SNO+: 44 events per year (1000 tons CH2) / 42 events reactor
Geo-Neutrino Signal
SNO+ geo-neutrinos and reactor background
- 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 m2 and 12
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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.
SNOLAB Construction is complete – Final cleaning occurring
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SNOLAB @ Neutrino 2008 Christchurch May 28th, 2008
SNOLAB
Personnel facilities
SNO Cavern
Ladder Labs
Cube Hall
Phase IICryopit
UtilityArea
2009: MiniCLEAN 3602010: DEAP/CLEAN 3600
Now:DEAP-1
2010: SNO+
2009: HALO
Now:PICASSO-II
New large scale project.
2011: SuperCDMS ?
2010: PICASSO IIB?2010: EXO-200-Gas?
All Lab Air: Class < 2000
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PersonnelFacility
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LunchRoom
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LunchRoom
Start of Clean conditions for the new SNOLAB: Feb. 2009
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Cube Hall
MiniCLEAN360 kg2009
DEAP/CLEAN3.6 tonne
2010
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 tonnes Ar)
WIMP-Induced Nuclear recoils in Ar are discriminated from beta and gamma radioactivity (39Ar) by timing of the light emitted.
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Dark Matter Search at SNOLAB with Liquid Argon
Yellow: Prompt light regionBlue: Late light region
)s9(TotalPE
)ns150(omptPEPrFprompt
Backgrounds (’s)
Signal (nuclear recoil)
DEAP-1 at SNOLAB
Backgroundsuppression better than2.6 E-8 demonstratedto date
For DEAP/CLEAN 3600suppression 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.
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CDMS-II: ~50 kg-days (Ge)XENON-10: ~300 kg-days (Xe)DEAP- 3600: 1,000,000 kg-days (Ar) (3 yrs)
SuperCDMS25 kg
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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
insensitive to beta and gamma radiation; some discrimination exists for alphas
19F favourable target to search for “spin-dependent” WIMP scattering
32 detector modulescontaining 4 L of gel
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Phase 1a: (published in ’05 PLB, NIM) 20g 2kgd
Phase Ib: (ongoing)2.6 kg 700 kgdBckg red. 1/6 – 1/10 Phase Ib/100:2.6 kg 700 kgdBckg: red. 1/100 Phase II:25 kg 7000 kgdLarger modules 30L
PICASSO PHASES
MSSMTheoryPredictions
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
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H eliumA ndL eadO bservatory
A lead detector forsupernova neutrinosin SNOLAB
Laurentian, TRIUMF, SNOLAB, LANL, Washington, Duke, Minnesota, Digipen IT HALO-1: 80 tons of existing Pb
& SNO Neutron Detector Array
Pb: Most sensitivity to electron neutrinos.~ 50 events for SN at center of Galaxy.
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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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