Status of R&D of the SuperNEMO experiment

Gwénaëlle Broudin-Bay

LAL Orsay

GDR neutrino – Bordeaux – 25-26 Oct. 2007

Search for neutrinoless double beta decay (Majorana and effective mass <mν> ?

0 : 2n 2p+2e-

ΔL = 2, beyond Standard Model2 : 2n 2p+2e-+2Allowed by the Standard Model

Association of calorimeter and trackingIdentification of e-, e+, , , neutrons, energy measurement

QE1+E2

Energy sum of the electrons

Arbi

tr ar y

un i

t

SuperNEMO experiment philosphy

GDR Neutrino – Bordeaux – Oct. 2007

From NEMO3 to SuperNEMO

7 kg 100-200 kg Isotope mass M

8 % ~ 30 %

Isotope 100Mo

150Nd or 82Se

T1/2 () > ln 2 M Tobs Nexclus

NA

A

NEMO-3 SuperNEMO

Internal contamination208Tl and 214Bi in ββ foil

208Tl: < 20 Bq/kg214Bi: < 300 Bq/kg

208Tl < Bq/kgif 82Se: 214Bi < 10 Bq/kg

T1/2() > 2 x 1024 y<m> < 0.3 – 1.3 eV

T1/2() > 2 x 1026 y<m> < 40 - 110 meV

Energy resolution (FWHM) 15% @ 1MeV 7% @ 1 MeV

Efficiency

GDR Neutrino – Bordeaux – Oct. 2007

USAMHCINL

U Texas

JapanU SagaU Osaka

FranceCEN Bordeaux

IPHC StrasbourgLAL ORSAY

LPC CaenLSCE Gif/Yvette

UKUCL

U ManchesterImperial College

FinlandU Jyvaskula

RussiaJINR DubnaITEP Mosow

Kurchatov InstituteUkraine

INR KievISMA Kharkov

Czech RepublicCharles U PrahaIEAP Praha

Slovakia(U. Bratislava)

About 60 physicists

SpainU Valencia

U SaragossaU Barcelona

PolandU Warsaw

The SuperNEMO collaboration

GDR Neutrino – Bordeaux – Oct. 2007

Modular design : ~ 100 kg of enriched isotopes (20 modules x 5 kg)

Conceptual design of the SuperNEMO detector

Per module: Source (40 mg/cm2) 4 x 3 m2

Tracking detector: Drift chamber ~3000 cells in Geiger mode

Calorimeter: scintillators + PMTs ~ 600 PMTs with blocks ~ 100 PMTs with bars

4 m

Top view5 m

1 m

SuperNEMO status

SuperNEMO design study (Feb. 2006 ~ Feb. 2009)

Large scale R&D approved in France, UK and Spain(Similar proposals under consideration in Russia, Czech, Japan.)

R&D work packagesCalorimeter – Energy resolution : 7% at 1 MeV (4% FWHM at 3 MeV)

Tracking detector -- optimization, wiring automation, test of prototypes.

Source – Ultra pure sources production (82Se and/or 150Nd), purity control. BiPo detector -- source foils radiopurity control (214Bi, 208Tl), sensitivity

A(208Tl) < 2 Bq/kg

Simulations GDR Neutrino – Bordeaux – Oct. 2007

Goals - Energy resolution 4% (FWHM) at 3 MeV (7% at 1 MeV) - Optimization of the geometry, number of channels…

R&D PHOTONIS (IN2P3/PHOTONIS agreement), Hamamatsu et ETL (UK)

Photomultipliers (8 ’’)

Quantum efficiency > 40%, collection efficiency Low radioactivity 40K< 100 mBq/kg, 214Bi, 208Tl < 10 mBq/kg

Scintillators

Homogeneity, light yield Liquid scintillator R&D prioritary (LAB)Advantages: - high light yield

- good uniformity - attenuation length> 10 m - flash point > 130 °C - non-corrosive - inexpensive (found in detergents)

energy measurement possible for e- et with a thickness of ~20 cm of scintillator

Plastic scintillator - Collaboration Kharkov, Dubna (PICS)Improvement of polystyrene, development of polyvinyltoluene Wrapping test: chemical treatment

Calorimeter R&D

Energy resolution 4.2% at 3 MeV measured with 7.5 x 7.5 x 20 cm LS + lightguide + 3’’ PMT

Liquid scintillator

Challenge: mechanical constraints in particular for the entrance window (electron detection)

R&D Scintillator

GDR Neutrino – Bordeaux – Oct. 2007

Tracking detector R&D

Optimization of cells length, diameter, wire material, gas mixture, read-out.Two 9-cell prototypes built.100 and 300-cell prototypes to be completed by early 2008.

GDR Neutrino – Bordeaux – Oct. 2007

Sources R&D : choice of the isotope

The choice of the isotope depends on:

Enrichment possibilityHigh Q value:

high phase space factor

lower non-2 background

Two candidates: 82Se and 150Nd

Isotope Q (MeV) G (y-1) Abundance %

48Ca 4.271 2.44 0.18776Ge 2.040 0.24 7.882Se 2.995 1.08 9.296Zr 3.350 2.24 2.8100Mo 3.034 1.75 9.6116Cd 2.802 1.89 7.5130Te 2.528 1.70 34.5136Xe 2.479 1.81 8.9150Nd 3.367 8.00 5.6

= G M ‹m›22T1/2

1

Long 2 half-life reduction of the 2 tail component of the backgroung

GDR Neutrino – Bordeaux – Oct. 2007

Sources R&D

• 3.5 kg of Se were enriched in Russia, funded by ILIAS. • Chemical purification at INL (USA).• Purification by distillation (Russia).• Enrichment of 100 kg of Se possible in two years in Russia.

• 150Nd production at the MENPHIS facility discussed.

• Meeting mid-november in the USA for an international between SNO+, KamLAND, SuperNEMO.

82Se

150Nd

GDR Neutrino – Bordeaux – Oct. 2007

BiPo detector R&D

e

time

~300 nsfor 212Bi (208Tl)

~ 164 sfor 214Bi

Two low-radioactivity plastic scintillatorsTime topology signature: 1 hit + 1 delayed hit

Measurement of the purity in 208Tl and 214Bi of the sources for SuperNEMO Goal: Measure the purity of 10 m2 of source (40 mg/cm2) in 1 month with a sensitivity of

208Tl < 2 Bq/kg and 214Bi < 10 Bq/kg inside the foil208Tl < 0,2 Bq/m2 and 214Bi < 1,25 Bq/m2 on the surface

(300 ns)

232Th

212Bi(60.5 mn)

208Tl(3.1 mn)

212Po

208Pb(stable)36

%

(164 s)238U

214Bi(19.9 mn)

210Tl(1.3 mn)

214Po

210Pb22.3 y0.

021%

Principle: Detection of the BiPo coincidence: β + α retardé

Prototype BiPo 1 Prototype BiPo2

Prototypes of the BiPo detector

2 scintillator plates (75 x 75 cm²)

Installation at the LSM in January 2008

4 capsules BiPo-1 running since July 2007

After 3 months of data-taking with ~ 0,32 m2 x month:A(208Tl) < 2.3 Bq/m² (90% C.L.)

Surface radiopurity required for 10 m²: A(208Tl) < 0.1 Bq/m2

GDR Neutrino – Bordeaux – Oct. 2007

R&D SuperNEMOR&D SuperNEMO

2007 2008 2009 2010 2011 2012 2013

NEMO3 RunningNEMO3 Running

RUNNING of RUNNING of full detectorfull detector

construction ofconstruction of20 modules 20 modules

SuperNEMO 1SuperNEMO 1stst module contructionmodule contruction

Final SuperNEMO modules installationFinal SuperNEMO modules installation

PreparationPreparationof the siteof the site

BiPo prototypeBiPo prototypeLSMLSM

BiPoBiPoconstructionconstruction

BiPo BiPo running @ Canfrancrunning @ Canfranc

6 SuperNEMO modules running @ Canfranc6 SuperNEMO modules running @ Canfranc

SuperNEMO Planning

TDR

TDR

GDR Neutrino – Bordeaux – Oct. 2007

Perspectives

SuperNEMO Phase I in Canfranc underground laboratory

Around 20 kg of enriched source (150Nd or 82Se)

2010 : beginning of the construction of the modules2012: 6-8 modules in Canfranc

SuperNEMO Phase II at LSM

100 –200 kg of enriched source (150Nd and 82Se)

Testing inverted hierarchy allowed

T½ > 2 1026 yr ( <m > < 50 meV )Sensitivity goal:

TDR planned 2009

GDR Neutrino – Bordeaux – Oct. 2007