nd double beta decay search with sno+

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Nd double beta decay search with SNO+ K. Zuber, on behalf of the SNO+ collaboration

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Nd double beta decay search with SNO+. K. Zuber, on behalf of the SNO+ collaboration. The SNO Detector. n. +. Þ. +. +. -. CC. d. p. p. e. e. n. +. Þ. +. +. n. NC. d. p. n. x. x. ES. -. -. +. Þ. +. e. e. x. x. SNO – The smoking gun. 1000 t heavy water (D 2 0). - PowerPoint PPT Presentation

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Page 1: Nd double beta decay  search with SNO+

Nd double beta decay search with SNO+

K. Zuber, on behalf of the SNO+ collaboration

Page 2: Nd double beta decay  search with SNO+

The SNO Detector

Page 3: Nd double beta decay  search with SNO+

SNO – The smoking gun

1000 t heavy water (D20)

CC-eppd

e

NCxx

npd

ES -- ee x x

)(14.0ES

CC

e

e

τμ

++=

CC

NC=

ν e

ν e + ν μ + ν τ

Page 4: Nd double beta decay  search with SNO+
Page 5: Nd double beta decay  search with SNO+

Original plan• 28 Nov. 2006: SNO finished data taking

Future plans:

• SNO+ : 1000 t Liquid scintillator real time low energy solar neutrinos (pep),geoneutrinos, reactor neutrinos

• SNO++: 1000t Nd-loaded scintillator double beta decay, geo- + reactor neutrinos

NOW: Do the Nd-loaded first! Can be quick and on a large scale

Page 6: Nd double beta decay  search with SNO+

SNO+

First collaboration meeting at Queens Univ. , May 30-31 (2007)

Page 7: Nd double beta decay  search with SNO+

SNO+- 1st collab. meeting

Page 8: Nd double beta decay  search with SNO+
Page 9: Nd double beta decay  search with SNO+

0: 1000 events peryear with 1% naturalNd-loaded liquidscintillator in SNO++

Test <m> = 0.150 eV

maximum likelihood statistical test of the shape to extract 0 and 2 components…~240 units of 2 significance after only 1 year!

Klapdor-Kleingrothaus et al., Phys. Lett. B 586, 198, (2004)

simulation:one year of data

Page 10: Nd double beta decay  search with SNO+

Nd-carboxylate in Nd-carboxylate in PseudocumenePseudocumene

made by Yeh, Garnov, Hahn at BNL

window with >6 m light attenuation length

{

Page 11: Nd double beta decay  search with SNO+

• at 1% loading (natural Nd), there is too much light absorption by Nd– 47±6 pe/MeV (from Monte

Carlo)

• at 0.1% loading (isotopically enriched to 56%) our Monte Carlo predicts– 400±21 pe/MeV (from Monte

Carlo)– good enough to do the

experiment

Concentration and Light Output

Page 12: Nd double beta decay  search with SNO+

external 241Am

Compton edge 137Cs207Bi conversionelectrons

Nd LS Works!small Nd-LS detector with , , sources demonstrates it works as scintillator

Page 13: Nd double beta decay  search with SNO+
Page 14: Nd double beta decay  search with SNO+

Petresa Plant – Petresa Plant – BBéécancour, QCcancour, QC

Page 15: Nd double beta decay  search with SNO+

2000–2003 Program : Menphis facility

Design : 2001Building : 20021st test : early 20031st full scale exp. : june 2003

EvaporatorDye laser chainYag laserCopper vapor laser

Page 16: Nd double beta decay  search with SNO+

AV Hold-downAV Hold-down

working on mechanical designworking on mechanical design SNO had rope basket support for the AV SNO had rope basket support for the AV

in an old design (+10% density in an old design (+10% density difference Ddifference D22O-HO-H22O)O)

believes optimization of above design believes optimization of above design can hold down 15% buoyancy can hold down 15% buoyancy (scintillator density (scintillator density = 0.85) = 0.85)

Page 17: Nd double beta decay  search with SNO+

SNO+ Double Beta SNO+ Double Beta SensitivitySensitivity

1 yr, 500 kg isotope, m = 150 meV

Page 18: Nd double beta decay  search with SNO+

Statistical Sensitivity in Statistical Sensitivity in SNO+ SNO+

500 kg isotope 56 kg isotope

• 3 sigma detection on at least 5 out of 10 fake data sets• 2/0 decay rates are from Elliott & Vogel, Ann. Rev. Nucl. Part. Sci. 52, 115 (2002)

corresponds to 0.1% natural Nd LSin SNO+

Page 19: Nd double beta decay  search with SNO+

• for 50% enriched 150Nd (0.1% Nd LS in SNO+)– statistical sensitivity is down to 30 meV– assumed background levels (U, Th) in the Nd LS to be

at the same level as KamLAND scintillator– systematic error in energy response will be the limit of

the experiment and not the statistics– preliminary studies show that if we understand the

resolution tails at the 10−4 level, we will preserve sensitivity around 50 meV

Statistical Sensitivity

Page 20: Nd double beta decay  search with SNO+

SNO+ “broad-brush” schedule

2007: removal of SNO heavy water, SNO+ design

2008: SNO+ installation 2009: Fill, run with pure scintillator 2010: Add Nd

Page 21: Nd double beta decay  search with SNO+

Summary

SNO+ plans to use a large amount of Nd-loaded scintillator withinthe existing SNO infrastructure

Could be rather fast

Seeking for more collaborators

Need some reliable 150Nd matrix element calculations