Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina...

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supported by: The SNO+ Experiment: Overview and Status DPG Spring Meeting Dresden 2013 Arnd Sörensen , Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig, Felix Krüger and Kai Zuber

Transcript of Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina...

Page 1: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

supported by:

The SNO+ Experiment: Overview and StatusDPG Spring Meeting Dresden 2013

Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig, Felix Krüger and Kai Zuber

Page 2: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Outline

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SNO+ = SNO + Liquid Scintillator ? Liquid Scintillator From SNO to SNO+

Phases of Operation Neodymium loaded Phase (0νββ with 150Nd) Pure Scintillator Phase

SNO+ @ TU Dresden

Summary & Outlook

Page 3: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Location

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@ SNOLab in Creighton Mine,

Sudbury, Canada deepest underground laboratory

2 km ≈ 6000 meter water

equivalent flat overburden

muon rate:

Page 4: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Detector

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acrylic vessel• 12 m diameter• 5 cm thickness

780 t liquid scintillator (LAB)

≈ 9100 PMTs in support structure (~ 54% coverage)

light-water shielding:• 1700 t inside• 5700 t outside

urylon liner and radon seal

Page 5: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Linear Alkyl benzene (LAB)

fluor: 2 g/L PPO (= 2,5-Diphenyloxazol) chemically compatible with acrylic long scattering length & high optical transparency high light yield (≈ 10,000 photons/MeV) high purity available inexpensive & safe

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LAB + PPO + (Nd)

Page 6: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

from SNO to SNO+

SNO SNO+

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LAB lighter than water:

rope hold up system + rope hold down system

Page 7: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

from SNO to SNO+

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General

• rope-net hold down system• new calibration (source

manipulation) system• scintillator purification plant

Page 8: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

from SNO to SNO+

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Electronics

• DAQ boards refurbished• improved data flow• replace & repair broken

PMTs• PMTs remapped

Page 9: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

from SNO to SNO+

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Calibration

• new low energy sources• optical calibration via fibre-

injected lasers and LEDs• variety of gamma, alpha,

beta and neutron sources

Page 10: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Phases of Operation

• detector commissioningwater phase

• 150Nd loaded into liquid scintillator

• reactor-, geo- and supernova- neutrinos

(neutrinoless-) double beta

decay

• search for solar neutrinos: pep and CNO

• reactor-, geo- and supernova- neutrinos

pure scintillator

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2013

2014 - 2017/?

2017 - ?

Page 11: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Neodymium loaded Phase

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• large isotope mass, low background

• poor energy resolution

neutrinoless 0vββ search with liquid scintillator

150Nd • high Q-value: 3.371 MeV

low background• fastest calculated decay rate• complementary to other 0vββ

experiments (76Ge, 136Xe …)

in SNO+ • LS successfully loaded with

Neodymium• 0.1% loading• optimisation: 0.3% loading

Page 12: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Neodymium loaded Phase

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• 0.1% Nd loading (43.7 kg 150Nd)

• mee = 350 meV

• 6.4% FWHM @3.37 MeV• IBM‐2 matrix element • 3 years running and• 50% fiducial Volume

(≈ 0.4 kt)• Borexino background levels

+ efficient tagging: 214Bi: 99.9% reduction 208Tl: 90.0% reduction

Background despite low Q-value through pile-up of e.g. 144Nd, 176Lu, 138La, 14C 99% pile-up rejection while keeping 90% signal in ROI

Page 13: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

0vββ with 150Nd

assuming Borexino background levels are reached and efficient tagging: 214Bi: 99.9% reduction 208Tl: 90.0% reduction

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[Nucl. Phys. B. (Proc. Supp.), S143:229, 2005]Claim of Klapdor mee ≈ 170 – 530 meV

0.3% Nd (9.0% FWHM @ 3.37 MeV)0.1% Nd (6.4% FWHM @ 3.37 MeV)

Page 14: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Solar Phase

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Complete our understanding of the solar neutrino fluxes: Super-K and SNO measured 8B neutrinos Borexino measured 7Be and first probed pep neutrinos pp was observed with Ga experiments

improve pep measurement still missing CNO (probe for solar metallicity)

Page 15: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

pep Neutrinos

single energy: 1.442 MeV very well predicted flux (≈ 2% uncertainty)

new physics models (NSI) predict different survival probabilities in vacuum matter transition regions

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[PLB 594, 347-354 (2004)] SNO, [arXiv:1109.0763]

Page 16: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

CNO Neutrinos

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[Pena-Garay & Serenelli, arXiv:0811.2424]

No direct observation of CNO neutrinos yet !

probe for solar core metallicity

new solar physics developments suggest 30% lower metallicity

old (high Z) new (low Z)

Page 17: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Reactor Neutrinos

Flux is 5 times less than KamLANDBUT

SNO+ reactor spectrum, including oscillations, have sharp peaks and minima, that increase the parameter-fitting sensitivity for Δm12

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no Oscillation 308 events

no Oscillation 1186 events

Oscillation 176 events

Oscillation 710 events

Page 18: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Geo Neutrinos

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Signal:

from β-decays in Earth’s mantle and continental crust (238U,232Th,40K)

local region extremely well studied due to mining low reactor-v background in SNO+: Reactor/Geo ≈ 1.1

check Earth heat production models / chemical composition (multi-site measurement in combination with Borexino, KamLAND)

Page 19: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

SNO+ @ TU Dresden

0vββ Phase• design, development and test of 48Sc calibration source (3.33 MeV - ROI)

T 103.8 – Axel Boeltzig• study of cosmogenic (n,p)- activation of Nd and LAB

• first measurement of natNd(p,x) cross sections [PRC 85, 014602 (2012)]• study of underground- and thermal- neutron activation of Nd

pure scintillator phase• sensitivity study to solar neutrinos and neutrino oscillation parameters• design, development and test of 57Co low energy (122 keV) calibration

source • to test the detector threshold and the low energy response

• alpha and proton quenching factor measurements [arXiv:1301.6403]• cosmogenic muons and muon induced background tagging• investigation of the 14C background

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Page 20: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Summary

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SNO+ succeeds the SNO experiment by replacing heavy water with

liquid scintillator LS has higher light yield and lower threshold allows to investigate lower

energy range ( E < 3.5 MeV ) two phases planned:

Nd loaded phase to search for 0vββ decay of 150Nd

pure scintillator phase to observe pep and CNO solar neutrinos reactor neutrino oscillation confirmation, geo neutrino investigation

at geologically-interesting site, supernova neutrino watch …

SNO+ will be filled with water this year 0vββ search starts next year

Page 21: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Thank you for your attention !

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Page 22: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

more

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Page 23: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

pep, CNO Neutrinos - background

radio purity: 14C is not a problem pep signal is at higher energy U, Th not a problem if one can repeat KamLAND scintillator purity 40K, 210Bi (Radon daughter) 85Kr, 210Po not a problem pep signal is at higher energy

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SNO+ Borexino

pep11C

CNOCNO 11C

pep

Page 24: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

Solar Phase

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p-p solar fusion chain

CNO cycle

Page 25: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

(stat) 1 year 2 years

pep 9.1% 6.5%8B 7.5% 5.4%

7Be 4% 2.8%

pp A few %?

CNO ~ 15%?Assuming Borexino-level backgrounds are

reached

Sensitivity Goals

Page 26: Supported by: DPG Spring Meeting Dresden 2013 Arnd Sörensen, Valentina Lozza, Nuno Barros, Belina von Krosigk, Laura Neumann, Johannes Petzoldt, Axel Boeltzig,

pep sensitivity as a function of run time

Assuming Borexino-level

backgrounds are reached