SNO+ solar neutrino program - underground.physics.berkeley.edu · JinPing - SNO+ Solar Freija...

JinPing - SNO+ Solar Freija Descamps, 09/06/2014

SNO+ solar neutrino program

Freija Descamps for the SNO+ collaboration

The SNO+ detector

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SNOLAB and SNO+ ✤ SNO+ = successor to Sudbury

Neutrino Observatory (SNO)!✤ Located in SNOLAB inside the

Creighton mine near Sudbury, Canada!

✤ Depth = 2070m (6000m.w.e)!✤ ~70 muons/day in SNO+!✤ Class-2000 clean room

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SNOLAB and SNO+ ✤ SNO+ = successor to Sudbury

Neutrino Observatory (SNO)!✤ Located in SNOLAB inside the

Creighton mine near Sudbury, Canada!

✤ Depth = 2070m (6000m.w.e)!✤ ~70 muons/day in SNO+!✤ Class-2000 clean room

Deck with DAQ SNO+ operator

~780T LAB liquid organic

scintillator!+ PPO

acrylic vessel!

⌀ 12m!5cm thick

~9500 PMTs!54% coverage

rock

~7kT ultra-pure water

shield

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Liquid scintillator ✤ LAB: Linear AlkylBenzene!

✤ Long attenuation length (~20m)!✤ Safe: low toxicity and high flash point !✤ Chemically compatible with acrylic!✤ α-β separation through scintillation

decay-times!✤ High light yield ~10000𝛄/MeV!✤ Fluor: 2.5-Diphenyloxazol (PPO)!

✤ 2g/L

NIM A640, 119-122 (2011)

Petresa plant!Bécancour, QC

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LAB purification plan

✤ Multi-stage distillation!✤ Removes heavy metals!✤ Improves UV transparency!✤ Dual-stream PPO distillation!

✤ N2/steam stripping!✤ Removes Rn, Kr, Ar, O2!

✤ Water extraction!✤ Removes Ra, K, Bi!

✤ Metal scavenging!✤ Removes Bi, Pb!

✤ Microfiltration!✤ Removes dust

4

Distillation Water extraction

C-200 Water Extraction Column


LAB purification plan

✤ Multi-stage distillation!✤ Removes heavy metals!✤ Improves UV transparency!✤ Dual-stream PPO distillation!

✤ N2/steam stripping!✤ Removes Rn, Kr, Ar, O2!

✤ Water extraction!✤ Removes Ra, K, Bi!

✤ Metal scavenging!✤ Removes Bi, Pb!

✤ Microfiltration!✤ Removes dust

4

Distillation Water extraction

Target levels:!85Kr: 10-25 g/g!40K: 10-18 g/g!39Ar: 10-24 g/g!U: 10-17 g/g!Th: 10-18 g/g

C-200 Water Extraction Column


SNO+ solar goals✤ What can neutrinos tell is about the Sun?!

✤ CNO flux measurement!✤ Direct pp measurement!

!✤ What can the Sun tell us about neutrinos?!

✤ Day/night asymmetry!✤ Precision pep flux!✤ Low-energy 8B spectrum

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Search for new physics in transition region

Confirm MSW

}

Resolve solar metallicityLuminosity constraint


SNO+ solar goals✤ What can neutrinos tell is about the Sun?!

✤ CNO flux measurement!✤ Direct pp measurement!

!✤ What can the Sun tell us about neutrinos?!

✤ Day/night asymmetry!✤ Precision pep flux!✤ Low-energy 8B spectrum

5

Search for new physics in transition region

Confirm MSW

}

Resolve solar metallicityLuminosity constraint

Non-standard physics effects can alter the shape / position of the “MSW rise”

Friedland, Lunardini, Peña-Garay,!PLB 594, (2004)


Survival probability

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Phys. Rev. D 88, 053010 (2013)


Solar Neutrinos

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SNO: LETA

First SNO


Solar Neutrinos

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SNO: LETA

First SNO

SNO+


✤ 39Ar!✤ 210Bi!✤ 11C!✤ 14C!✤ 40K!✤ 85Kr!✤ 210Pb!✤ 210Po!✤ U chain!✤ Th chain

Backgrounds

Cosmogenic!e.g. 11C, 10C

External !AV, PMTs,

H2O, ropes

Internal!LS,!

water, AV leaching,!

internal ropes!e.g. 14C, 210Bi,

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U and Th chains

✤ Purification techniques!✤ Direct background α

and β emissions!✤ Coincidence

techniques are under investigation, ex.:!✤ β-α ⇾ 214Bi-214Po!✤ β-α ⇾ 212Bi-212Po !✤ α-β ⇾ 212Bi-208Tl!✤ 95-99.9% rejection!

✤ 50% fiducial volume cut to reject external backgrounds

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visible energy [MeV]0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Cou

nts

per 0

.1 k

tons

per

1.0

yea

rs p

er 5

keV

-110

1

10

210

310

410pppepbe7b8cnoc11-decays

pppepbe7b8cnoc11-decays

resolutionEAnalytically generated spectra with 5%/

Borexino

11C background

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11C produced by cosmic μ hitting!organic molecules

KamLAND: 2700 mwe!Borexino: 3500 mwe!SNO+: 6080 mwe!Jinping: 7500 mwe


Cou

nts

per 0

.1 k

tons

per

1.0

yea

rs p

er 5

keV

-110

1

10

210

310




Borexino



Cou

nts

per 0

.1 k

tons

per

1.0

yea

rs p

er 5

keV

-110

1

10

210

310




Borexino

11C background

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11C produced by cosmic μ hitting!organic molecules

KamLAND: 2700 mwe!Borexino: 3500 mwe!SNO+: 6080 mwe!Jinping: 7500 mwe


Cou

nts

per 0

.1 k

tons

per

1.0

yea

rs p

er 5

keV

-110

1

10

210

310




Borexino


Cou

nts

per 0

.4 k

tons

per

1.0

yea

rs p

er 5

keV

-110

1

10

210

310




SNO+


Energy / MeV1 2 3 4 5 6

Even

ts / k

Tonn

e-ye

ar

1

10

210

310

Sum8B7BeCNOpep

228Ac210Bi

�212Bi 214Bi40K234Pa214Pb212Po208Tl

SNO+ solar neutrino spectrum

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Assuming initial Borexino-level backgrounds are reached


Energy / MeV0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Even

ts / k

Tonn

e-ye

ar

210

310

Sum8B7BeCNOpep

228Ac210Bi

�212Bi 214Bi40K234Pa214Pb212Po208Tl

SNO+ low-energy

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Energy / MeV0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Even

ts / k

Tonn

e-ye

ar

210

310

Sum8B7BeCNOpep

228Ac210Bi

�212Bi 214Bi40K234Pa214Pb212Po208Tl

Sum w/o pep

SNO+ low-energy

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Energy / MeV0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Even

ts / k

Tonn

e-ye

ar

210

310

Sum8B7BeCNOpep

228Ac210Bi

�212Bi 214Bi40K234Pa214Pb212Po208Tl

Sum w/o pep

SNO+ low-energy

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Energy / MeV0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Even

ts / k

Tonn

e-ye

ar

210

310

Sum8B7BeCNOpep

228Ac210Bi

�212Bi 214Bi40K234Pa214Pb212Po208Tl

Sum w/o pep5% energy scale

SNO+ low-energy

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Energy / MeV0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Even

ts / k

Tonn

e-ye

ar

210

310

Sum8B7BeCNOpep

228Ac210Bi

�212Bi 214Bi40K234Pa214Pb212Po208Tl

Sum w/o pep1% energy scale

SNO+ low-energy

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SNO+sensitivity studies!1 year lifetime!4 ν signals: pep, 7Be, 8B, CNO!30 bkgs!Th chain eqm!U chain semi-eqm!Extended max L fit!50% fid vol!Target bkgs!Energy scale /resn studies!Stat dominated

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1

1

10

210

310

410

510Sum

�8B �7Be

CNO+210Bi�pep

39Ar40K85Kr210Po14CU chainTh chain



SNO+sensitivity studies

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(stat) 1 year 2 years

pep 9.1% 6.5%

8B 7.5% 5.4%

7Be 4% 2.8%

pp A few %?

CNO ~ 15%?

Sensitivity goals

1 2 3 4 5 6

1

10

210

310

410

510 = 419.70163 / 6302�

: �B 8 679.79 +/- 24.39: �Be 7 53785.86 +/- 3067.64

: �Bi + CNO 210 21105.86 +/- 955.53: �pep 3553.48 +/- 305.40

1 year livetime50% fiducial volume

4 υ signals+ 7 bkgs


pp depends on 14C, 85Kr CNO depends on 210Bi


SNO+sensitivity studies

!8B spectrum!Background rejection:!

99.8% 214Bi through β - α tagging!90% 208Tl through α - α tagging

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Reactor neutrinos

SNO+ Physics Plan

!

Light Water filling now!!!! Scintillator loading (spring 2015)!

Te-loaded scintillator (end 2015)!

!

Pure scintillator phase!

Supernova monitoring

Geo neutrinos

ββ

backgrounds

nucleon decay

solar neutrinos

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