SNOW 2006, StockholmNEMO 3 and SuperNEMO experiments Vladimir Vasiliev, UCL 2-6 May ’06, Stockholm on behalf of NEMO and SuperNEMO collaborations NEMO

SNOW 2006, StockholmNEMO 3 and SuperNEMO experiments

Vladimir Vasiliev,UCL2-6 May ’06, Stockholm

on behalf of NEMO and SuperNEMO collaborations

NEMO collaboration: IReS, Strasbourg, France; LAL, Orsay, France; INEEL, Idaho Falls, USA; ITEP, Moscow, Russia; CENBG, Bordeaux-Gradignan; JINR, Dubna, Russia; IEAP, Prague, Czech Republic; UCL, London, UK; LPC, Caen, France; Saga Universityt, Japan; LSCE, Gif-sur-Yvette, France; Jyvaskyla University, Finland; MHC, South Hadley, USA; Charles University, Prague, Czech Republic; Manchester University, UK.

SuperNEMO collaboration: CENBG Bordeaux-Gradignan; IReS, Strasbourg, France; LAL, Orsay, France; LPC, Caen, France; LSCE Gif-Sur-Yvette, France; Jyvaskula Uiversity, Finland; Saga University, Japan; Osaka University, Japan; Fes University, Marocco; INR RAS, Moscow, Russia; ITEP, Moscow, Russia; JINR, Dubna, Russia; RRC Kurchatov Institute, Moscow, Russia; Charles University, Prague, Czech Republic; Technical University, Prague, Czech Republic; Manchester University, UK; UCL, London, UK; ISMA, Kharkov, Ukraine; INEEL Idaho Falls, USA; Mount Holyoke College, USA; University of Texas, USA; IFIC, Valencia, Spain; Canfranc laboratory, Zaragosa, Spain;

NEMO 3 and SuperNEMO experiments


Neutrinoless decay

Experimental signature:

a) 2 electronsb) E+ EQ

NEMO 3. Tracking experiment a) and b). Better signature, control and suppression of background. But worse resolution.

Ultimate background – decay tail.


3 m

4 mB (25 G)

20 sectors

NEMO-3 detectorFrejus underground laboratory 4800 m.w.e.

Source: 10 kg of isotopes, foil ~ 50mg/cm2

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

xy=0,6 cm; z=1,3 cm;

Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTsFWHM=14% (5”); 17% (3”) @ 1MeV

Time resolution = 0.25 ns @ 1MeV detection efficiency ≈ 50 %

Magnetic field: 25 Gauss (3% e+/e- confusion @ 1 MeV)

Gamma shield: Iron (e = 18 cm)Neutron shield: 30 cm water + boron (ext. wall); 40 cm wood (top and bottom)

Able to identify e, e, and


isotope foils

scintillators

PMTs

Calibration tube

Cathodic rings Wire chamber


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

Background measurement

search

isotopes in NEMO-3


Background model External background

Detector radioactivity (PMT, iron, flux from lab). Measured by Compton scattering in the foil.

Radon in tracking chamber 214Bi pollution of wires and foil surfaces. Measured

by delayed 214Po -decay. Source foil

Internal radioactivity. e and eevents from foil. decay

Cu foil


Radon free air facility

compressor9-10 bar

buffer

dryer

adsorption unit @ -50°C

cooler & heater

15 Bq/m3

15 mBq/m3

In the tent around NEMO 3 Rn = 150 mBq/m3 In the tracker Rn = 4.5 mBq/m3 does not depend any more from Rn level in the tent.

2 sets of dataPhase-I, before 4/10/04, Rn ≈ 22.2 mBq/m3, Phase-II, Rn=4.5 mBq/m3


results for 100Mo

T1/2 = 7.11 0.02 (stat) 0.54 (syst) 1018 yPhys Rev Lett 95, 182302 (2005)

SSD model confirmed

HSD, higher levels contribute to the decay

SSD, 1 level dominates in the decay (Abad et al., 1984, Ann. Fis. A 80, 9)

100Mo

0

100Tc

1

Decay to the excited 0+ state of 100RuT1/2 = 5.7 1.3 (stat) 0.8 (syst) 1020 y

To be published soon

Phase I + II ( 587d)Use MC Limit approach: shape information, different background level for PI and PIIE1+E2>2 MeV12952 evs MC = 12928 ± 70

TT1/21/2 > 5.6∙10 > 5.6∙102323 y, 90% CL y, 90% CL

Window method [2.78-3.20] MeV, (690d)Window method [2.78-3.20] MeV, (690d)14 evs MC = 13.4 =8.2 %

TT1/21/2 > 5.8∙10 > 5.8∙102323 y, 90% CL y, 90% CL

Simkovic, J. Phys. G, 27, 2233, 2001

Single electron spectrum different between SSD and HSD

Esingle (keV)

SSD simulation


results for 82Se

T1/2 = 9.6 0.3 (stat) 1.0 (syst) 1019 yPhys Rev Lett 95, 182302 (2005)

Phase I + II ( 587d)Use MC Limit approach

E1+E2>2 MeV238 evs MC = 240.5 ± 7

TT1/21/2 > 2.7∙10 > 2.7∙102323 y, 90% CL y, 90% CL

Window method [2.62-3.20] MeV, (690d)Window method [2.62-3.20] MeV, (690d)7 evs MC = 6.4 =14.4 %

T > 2.1∙10T > 2.1∙102323 y, 90% CL y, 90% CL


decay for other isotopes

116Cd, T1/2=(2.8±0.1(stat)±0.3(syst))∙1019 y

150Nd , T1/2=(9.7±0.7(stat) ±1.0(syst))∙1018y

96Zr, T1/2 =(2.0±0.3(stat)±0.2(syst))∙1019y

48Ca, T1/2=(5.3±0.9(stat)±0.5(syst))∙1019 y

Very preliminary results, to be crosschecked and published soon


Exotic processes search

V+A current in electroweak lagrangian Neutrino coupled axions (majorons)

V+A * n=1 ** n=2 ** n=3 ** n=7 **

Mo >3.2∙1023

<1.8∙10-6 [1]

>2.7∙1022

g<(0.4-1.8)∙10-4 [3]

>1.7∙1022 >1.0∙1022 >7∙1019

Se >1.2∙1023

2.8∙10-6 [2]

>1.5∙1022

g<(0.7-1.9)∙10-4 [3]

>6.0∙1021 >3.1∙1021 >5.0∙1020

* new PI+PII data** R.Arnold et al. Nucl. Phys. A765 (2006) 483NME Calculations:[1] J. Suhonen, Nucl. Phys. A 700 (2002) 649[2] M. Aunola and J. Suhonen, Nucl. Phys. A 463 (1998) 207[3] F. Simkovic et al., Phys. Rev. C 60 (1999) 055502; S.Stoica and H. Klapdor-Kleingrothaus, Nucl. Phys. A 694 (2001) 269; O. Civatarese and J. Suhonen, Nucl. Phys. A 729 (2003) 867


SuperNEMO project

extension of NEMO 3 technique 100 kg of isotopes, thin source between tracking

volumes, surrounded by calorimeter. sensitivity 1-2∙1026 y, 40-70 meV main improvements needed:

energy resolution (8% FWHM @ 1MeV ≡ 4% @ 3MeV)

detection efficiency (factor 2) source radio purity (factor 10) background rejection methods


SuperNEMO milestones

2006-8: Design studyCalorimeter

Tracker

Source

Site selection (Frejus, Gran Sasso, Canfranc, Bulby)

Approved and funded R&D program in UK and France. Spain, Russian and Japan groups applied for funding.

end 2008: Full Proposal

2009 – 2011: Production

2010-2011: Start taking data

2015: planned sensitivity ~0.04 eV


Modular design

Top view Side view

5 m

1 m 4 m

source

tracker

calorimeter


Alternative design (bar scintillator)

Double sided readout


Calorimeter R&D so far

7-8% FWHM @ 1MeV for small scintillator 5x5x2 cm

9% FWHM @ 1 MeV for 15x15x2 cm … but because of light guide!

11-13% FWHM @ 1 MeV for 200 cm bar scintillator.

Attenuation length 150 cm! looking for better plastic.


Wiring robot

The challenge:from 6,000 to~60,000+ cells

Wires must be strung terminated crimped

This can not be done manually (~10 min/wire)

Complications Copper pick-ups Must be cost effective Solder can not be used (radiopurity)


BiPo device, ultra low purity msr.

Tracking (wire chamber)

Shield radon, neutron,

Source foil (40 mg/cm2)

Scintillator + PMT

2 modules 23 m2 → 12 m2

Background < 1 event / month

(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%

Bi-Po Process

WHY? spectroscopy doesnt sensitive to purity level required ~10 Bq/kg

delay

e

Q(214Bi)=3.2 MeQ (212Bi) = 2.2 MeV

e

e prompt

T1/2 ~ 300 ns Edeposited ~ 1 MeV

Delay


Isotope choice

Detector allows to hold any isotope. Choice depends on: - enrichment possibilities. Obligatory!- Q value (phase space factor, background)- life-time

82Se good candidate 100 kg per 2-3 y enrichment rate possible in Russia Q

= 2995 keV. Concern about 214Bi and 208Tl only. test 2kg sample produced. Under purification now

150Nd even better! SILVA group (SACLAY, France) was contacted. 150Nd enrichment is possible! Q

= 3367 keV. Concern about 208Tl only Large phasespace. 2tale only 1.6 bigger then for 82Se NME & G much better then for 82Se


Conclusion

NEMO 3 is continuing to take data no signal so far.100Mo: T1/2>5.8∙1023 y; m<0.6-1.0 eV*

82Se: T1/2>2.1∙1023 y; m<1.2-2.5 eV*

*F. Simkovic et al., Phys. Rev. C 60 (1999) 055502; S.Stoica and H. Klapdor-Kleingrothaus, Nucl. Phys. A 694 (2001) 269; O. Civatarese and J. Suhonen, Nucl. Phys. A 729 (2003) 867 a number of results to be published soon SuperNEMO R&D is in progress. 3 year program

funded in UK and France.

WE ARE IN THE MIDDLE OF THE ROAD

EXIT

THAT COULD LEAD BEYOND SM

thank you for your attention!

Documents

SNOW 2006, StockholmNEMO 3 and SuperNEMO experiments Vladimir Vasiliev, UCL 2-6 May ’06, Stockholm on behalf of NEMO and SuperNEMO collaborations NEMO