Vladimir Vasiliev, UCL

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NEMO 3 and SuperNEMO experiments
Vladimir Vasiliev, UCL 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
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Neutrino, the story

• Proposed by W. Pauli in 1930
• Reactor ne observed,1953
• ne? nm, 1960-64
• Electro-weak theory GWS
• Neutral current discovered, 1973
• Z, W observed at LEP, 1983
• Z width ? 3 n families
• nt,
• SM almost complete.

Neutrino oscillate!
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Neutrino oscillations.
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Present experimental status
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Dirac neutrino
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Majorana neutrino
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See-Saw
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Double beta (bb) decay
Nucleus Q(keV) Abudance()
48Ca 4271 0.187
82Se 2995 9.2
96Zr 3350 2.8
100Mo 3034 9.6
116Cd 2802 7.5
130Te 2533 34.5
150Nd 3367 5.6
(A,Z)?(Z2,A)2e-2ne
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Neutrinoless bb decay

• Golden plated channel
• 2 electrons
• Eb1 Eb2Qbb

ltmgt2/E
(A,Z)?(Z2,A)2e-
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NEMO experiment

• Strategy
• Tracking device ? detect electrons
• Calorimeter ? measure its energy
• Full event signature ? background rejection
• Thin foil source ? virtually any isotope

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NEMO experiment, story
NEMO-1 1991
NEMO-3 2003
SuperNEMO 2011?
NEMO-2 1995
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NEMO-3 detector
Frejus 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 sxy0,6
cm sz1,3 cm Calorimeter 1940 plastic
scintillators coupled to low radioactivity
PMTs FWHM14 (5) 17 (3) _at_ 1MeV Time
resolution 0.25 ns _at_ 1MeV g detection
efficiency 50
Magnetic field 25 Gauss (3 e/e- confusion _at_ 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, g and a
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(No Transcript)
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bb isotopes in NEMO-3
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Radioactive background
Internal background
Source chemical purification
External background
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Radon free air facility
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
data Phase-I, before 4/10/04, Rn 22.2 mBq/m3,
Phase-II, Rn4.5 mBq/m3
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Background model

• External background
• Detector radioactivity (PMT, iron, g flux from
  lab). Measured by g Compton scattering in the
  foil.
• Radon in tracking chamber
• 214Bi pollution of wires and foil surfaces.
  Measured by delayed 214Po a-decay.
• Source foil
• Internal radioactivity. e and eg events from
  foil.
• bb2n decay

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bb results for 100Mo
T1/2 7.11 0.02 (stat) 0.54 (syst) ? 1018
y Phys Rev Lett 95, 182302 (2005)
SSD model confirmed
Decay to the excited 0 state of 100Ru T1/2 5.7
1.3-0.9 (stat) 0.8 (syst) ? 1018 y Nucl.
Phys. A in press

• bb0n Phase I II ( 587d)
• Binned LH shape information, different
  background level for PI and PII
• E1E2gt2 MeV
• 12952 evs MC 12928 70 e0n18.1
• T1/2 gt 5.61023 y, 90 CL
• Window method 2.78-3.20 MeV, (690d)
• 14 evs MC 13.4 e0n8.2
• T1/2 gt 5.81023 y, 90 CL

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bb results for 82Se
T1/2 9.6 0.3 (stat) 1.0 (syst) ? 1019
y Phys Rev Lett 95, 182302 (2005)

• bb0n Phase I II ( 587d)
• Use of binned LH
• E1E2gt2 MeV
• 238 evs MC 240.5 7 e0n17.6
• T1/2 gt 2.71023 y, 90 CL
• Window method 2.62-3.20 MeV, (690d)
• 7 evs MC 6.4 e0n14.4
• T1/2 gt 2.11023 y, 90 CL

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bb2n decay for other isotopes
116Cd, T1/2(2.80.1(stat)0.3(syst))1019 y
150Nd , T1/2(9.70.7(stat) 1.0(syst))1018y
96Zr, T1/2 (2.00.3(stat)0.2(syst))1019y
48Ca, T1/2(5.30.9(stat)0.5(syst))1019 y
Preliminary results, to be crosschecked and
published soon
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New physics, VA current
Mass term
? term
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New physics, ? serach.

• B-L could be broken not explicitly (e.g. with
  majorana mass term in L) but spontaneously
  (similar to W and Z mass)
• Goldstone theorem implies new boson, ?, to exist.
  
• (A,Z)?(Z2,A)2e-?( ?)

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Exotic processes search
VA , only l term n1 ,y n2 ,y n3 ,y n7 ,y
Mo gt3.21023 llt1.810-6 1 gt2.71022 glt(0.4-1.8)10-4 3 gt1.71022 gt1.01022 gt71019
Se gt1.21023 llt2.810-6 2 gt1.51022 glt(0.7-1.9)10-4 3 gt6.01021 gt3.11021 gt5.01020
new PIPII data R.Arnold et al. Nucl. Phys.
A765 (2006) 483 NME 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
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SuperNEMO project

• extension of NEMO 3 technique
• 100 kg of isotopes, thin source between tracking
  volumes, surrounded by calorimeter.
• sensitivity 1-21026 y, 40-70 meV
• main improvements needed
• energy resolution (8 FWHM)
• detection efficiency (factor 2 better)
• source radio purity (factor 10 better)
• background rejection methods

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SuperNEMO milestones

• 2006-8 Approved and funded technical design
  study
• Calorimeter
• Tracker
• Source
• Site selection
• end 2008 Full Proposal
• 2009 2011 Production
• 2010-2011 Start taking data
• 2015 Reach planned sensitivity 0.04-0.07 eV

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SuperNEMO design (early stage)
Single sub-module with 7 kg of isotope (30-50
mm foil)
15 sub-modules for 100 kg of isotope surrounded
by passive shielding

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SuperNEMO design
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Alternative design (bar scintillator)
Double sided readout
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Calorimeter RD so far

• 7-8 FWHM _at_ 1MeV for small scintillator 5x5x2 cm

• 9 FWHM _at_ 1 MeV for 15x15x2 cm due to light
  guide struggling for optical contact!

• 11-13 FWHM _at_ 1 MeV for 200 cm bar scintillator.

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How to improve resolution?
Z. Li et al, NIM A 552 (2005) 449
11000 ph/MeV
6708 ph/MeV

• Move scintillator emission spectrum
• Extend PM sensitivity to green
• Expect to reach 5 FWHM_at_1MeV

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Tracker optimization
Optimize length (check if 4m works), wire
material and diameter, gas mixture etc 9-cell
prototype built (Manchester) 100 cell prototype
to be built by October 2007
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Wiring robot
The challenge from 6,000 to 60,000
cells 400,000 wires

• Wires must be
• strung
• terminated
• crimped
• This can not be done
• manually (10 min/wire)

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Isotope choice

• Detector allows to hold any isotope. Choice
  depends on
• - enrichment possibilities. Obligatory!
• - Qbb value (phase space factor, background)
• - bb(2n) life-time

• 82Se good candidate
• 100 kg per 2-3 y enrichment rate possible in
  Russia
• Qbb 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!
• Qbb 3367 keV. Concern about 208Tl only
• Large phasespace. 2n tale only 1.6 bigger then
  for 82Se
• NME G0n much better then for 82Se

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BiPo device, ultra low purity msr.
WHY? g spectroscopy doesnt sensitive to purity
level required 10 mBq/kg
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BiPo device, ultra low purity msr.
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Software development

• Full MC simulation under development
• GEANT4 for low energy physics simulation
• Use NEMO-3 data for accurate tracking chamber and
  calorimeter response simulation
• DECAY-4 library for decay kinematics (bb and all
  radioactive backgrounds)
• Cellular automate Kalman filter for track fit
• Will be used to provide input for TDR

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Conclusion

• NEMO 3 is continuing to take data
• no bb0n signal so far.
• 100Mo T1/2gt5.81023 y mnlt0.6-1.0 eV
• 82Se T1/2gt2.11023 y mnlt1.2-2.5 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 bb2n results to be published soon
• SuperNEMO RD is in progress. TDR to be done by
  February 2009