Warsaw - NEMO initiative group

Zenon Janas

for

Search for neutrinoless double decay

in

NEMO-3 and SuperNEMO experiments

Warszawa, 03.07.2006

Warsaw - NEMO initiative group

W. Dominik, IFD UW

Z. Janas, IFD UW

T. Matulewicz, IFD UW

M. Pfutzner, IFD UW

E. Rondio, SINS........

Double beta decay

Main decay modes:

(A, Z) (A, Z+2) + 2e

2

0

(A, Z) (A, Z+2) + 2 e + 2 e

(A, Z)

(A, Z+1)

(A, Z+2)

L = 0

L = 2

Energy spectra of emitted electrons

arb

itra

ry u

nit

s

(Q ~ MeV)

220v0102/1 mMGT

Neutrinoless decay rate

Motivation of 0 decay studies

• neutrino nature: Dirac or Majorana ?

• absolute neutrino mass scale

• neutrino mass hierarchy

• Majoron emission ?

Tracking + calorimeter

Both techniques are complementary !!

only total energy measured

high energy resolution

good efficiency

compact detectors ( 10 m)

very pure crystals

source specific

Experimental approaches in decay studies

Calorimeter

HPGe – Te bolometers NEMO

individual electrons observed

modest energy resolution

small efficiency

large detector size ( 50 m)

background measured

universal

3 m

4 m

B (25 G)

20 sectors Location: Fréjus Underground Lab. 4800 m.w.e.

Source: 10 kg of isotopes (100Mo) cylindrical, S = 20 m2, 60 mg/cm2

Tracking detector: drift wire chamber operating in Geiger mode (6180 cells)Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O

Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs

NEMO-3 detector

Ability to identify e, e, and © S. Julian, LAL

Criteria to select events• 2 tracks with charge < 0• 2 PMT, each > 200 keV• PMT-Track association • Common vertex

• Internal hypothesis (external event rejection)• No other isolated PMT ( rejection)• No delayed track (214Bi rejection)

Deposited energy: E1+E2= 2088 keVInternal hypothesis: (t)mes–(t)theo = 0.22 nsCommon vertex: (vertex) = 2.1 mm

Vertexemission

(vertex)// = 5.7 mm

Vertexemission

Transverse view Longitudinal view

Typical 2 event observed from 100Mo isotope

Trigger: at least 1 PMT > 150 keV

3 Geiger hits (2 neighbour layers + 1)

Trigger rate = 5.8 Hz

events: 1 event every 2.5 minutes

2 decay of 100Mo

T1/2(100Mo,2) = [ 7.11 ± 0.02 (stat) ± 0.54 (syst) ] 1018 yT1/2(100Mo,2) = [ 7.11 ± 0.02 (stat) ± 0.54 (syst) ] 1018 y

cos(ee)E1 + E2 (MeV)

219 000 evnts6914 g

389 days

219 000 evnts6914 g

389 days

2 sim.bgnd

Data

Sum Energy Spectrum Angular Distribution

2 sim.bgnd

Data

2.8 - 3.2 MeV range

Nobserved = 7 events

bgnd = 8.1 ± 1.3

0 decay of 100Mo

T1/2(100Mo,0) > 4.6 1023 y

<m> < 0.7 – 2.8 eV

T1/2(100Mo,0) > 4.6 1023 y

<m> < 0.7 – 2.8 eVR. Arnold et al., PRL 95 (2005) 182302

Plane geometry, 20 modules

Top view5 m

1 m

1 module: source: 34 m2 40 mg/m2 of enriched isotope

tracking volume: ~ 3000 drift chamber cells

calorimeter: ~ 1000 scintillators + PMTs

SuperNEMO - preliminary design

© S. Julian, NEMO-3 collaboration

NEMO-3 SuperNEMO

From NEMO-3 to SuperNEMO

7 kg 100 kg Mass of isotope

Efficiency () = 8 % () ~ 20 %

Isotope 100Mo

T1/2() = 7 x 1018 y

82SeT1/2() = 1020 y

~ 1 evt/ 100 kg / y ~ 1 evt / 7 kg / y

T1/2() > 2 x 1024 y

<m> < 0.3 – 1.3 eV

T1/2() > 2 x 1026 y

<m> < 0.04 – 0.1 eV

SENSITIVITYafter 5 years

Resolution~ 11 % at 3 MeV ~ 7 % at 3 MeV

208Tl and 214Bi background

Most promissing 0 projects

A.S. Barabash, arXiv:hep-ex/0602037

2005 - 2007 - R&D program

2008 - construction of the SuperNEMO module with 5 kg 82Se

2009 - 2011 - construction and installation of the 20 modules, start taking data with delivered modules

2012 - full SuperNEMO running with 100 kg of 82Se

Plans for SuperNEMO

SuperNEMO collaboration

Kurchatov Inst. Moscou, RussiaKarkhov UkraineManchester University, UKUCL London, UKINL Idaho Falls, USAMHC Massachusets , USASaga Univ., JapanTexas Univ. Austin, USA

CENBG Bordeaux, FranceIReS Strasbourg, FranceLAL Orsay, FranceLPC Caen, FranceLSCE Gif sur Yvette, FranceFNSPE Prague Univ., Czech Rep.ITEP Moscow, RussiaJINR Dubna, Russia

R&D tasks in the SuperNEMO collaboration

SuperNEMO R&D

Source

Enrichment

Purification

Foils prod.

Calorimeter

Scintillators

PMT

Drift Chamb

Prototype

Autom. wiring

Radiopurity

HPGe spectr

BiPo det.

Radon det.

MechanicsComputing

Simulation

Electronics

Calorimeter

Drift chamb

Trigger

© S. Julian, LAL

Possible contribution of Polish group:

- data analysis

• NEMO-3

- modeling and simulations

- main detector design and construction

- data analysis

- detector for purity control of drift chamber gas

• SuperNEMO

Detector for purity control of drift chamber gas

a possibility: Optical Time Projection Chamber

gas

CCD PMT

drift 1 s/cm

amp.

WLS

e

M. Ćwiok et al., IEEE TNS, 52 (2005) 2895

Performance of the OTPC

13O

p

K. Miernik et al.

Water shield ( 2 ktons)

Source foil

14 m

Needed cavity:

~60 x 15 x 15 m

Location: Modane, Gran Sasso …?

Full detector

3,75 m © S. Julian, LAL

20 modules: 100 kg of enriched isotope

100Mo 6.914 kg Q= 3034 keV

82Se 0.932 kg Q= 2995 keV

116Cd 405 g Q= 2805 keV

96Zr 9.4 g Q= 3350 keV

150Nd 37.0 g Q= 3367 keV

Cu 621 g

48Ca 7.0 g Q= 4272 keV

natTe 491 g

130Te 454 g Q= 2529 keV

measurement

External bkg measurement

search (all enriched isotopes produced in Russia)

100Mo purified in INL (USA) and ITEP (Russia)

sources in the NEMO-3 detector