Prsentation PowerPoint

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NEMO-3 Experiment Neutrino Ettore Majorana
Observatory FIRST RESULTS
Xavier Sarazin 1 for the NEMO-3
Collaboration CENBG, IN2P3-CNRS et Université de
Bordeaux, France Charles University, Praha, Czech
Republic CTU, Praha, Czech Republic INEEL, Idaho
Falls, USA IReS, IN2P3-CNRS et Université de
Strasbourg, France ITEP, Moscou, Russia JINR,
Dubna, Russia Jyvaskyla University, Finland 1
LAL, IN2P3-CNRS et Université Paris-Sud,
France LSCE, CNRS Gif sur Yvette, France LPC,
IN2P3-CNRS et Université de Caen, France Mount
Holyoke College, USA RRC Kurchatov Institute,
Moscow, Russia Saga University, Saga, Japon UCL,
London, Great-Britain
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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• Plan of the talk
• NEMO-3 Detector
• Measurement of bb2n decay for several nuclei
• Search for bb0n decay with 100Mo and 82Se

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The NEMO3 detector
Fréjus Underground Laboratory 4800 m.w.e.
Source 10 kg of ?? isotopes cylindrical, S
20 m2, e 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
Xavier Sarazin for the NEMO-3 Collaboration

Neutrino 2004 Paris 14-19 June 2004
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Cathodic rings Wire chamber
PMTs
Calibration tube
scintillators
bb isotope foils
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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AUGUST 2001
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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NEMO-3 Opening Day, July 2002 Start taking data
14 February 2003
Water tank
wood
coil
Iron shield
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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bb decay isotopes in NEMO-3 detector
116Cd 405 g Qbb 2805 keV
96Zr 9.4 g Qbb 3350 keV
150Nd 37.0 g Qbb 3367 keV
48Ca 7.0 g Qbb 4272 keV
130Te 454 g Qbb 2529 keV
External bkg measurement
100Mo 6.914 kg Qbb 3034 keV
82Se 0.932 kg Qbb 2995 keV
natTe 491 g
Cu 621 g
(All the enriched isotopes produced in Russia)
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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bb events selection in NEMO-3
Typical bb2n event observed from 100Mo
Transverse view
Run Number 2040 Event Number 9732 Date
2003-03-20
Longitudinal view
100Mo foil
100Mo foil
Geiger plasma longitudinal propagation
Scintillator PMT
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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Performance of the detector
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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Measurement of 2b2n decay in NEMO-3
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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100Mo 2?2? preliminary results
(Data 14 Feb. 2003 22 Mar. 2004)
Sum Energy Spectrum
Angular Distribution
145 245 events 6914 g 241.5 days S/B 45.8
145 245 events 6914 g 241.5 days S/B 45.8
NEMO-3
NEMO-3
100Mo
100Mo
2?2? Monte Carlo
Background subtracted
2?2? Monte Carlo
Background subtracted
Cos(?)
E1 E2 (keV)
T1/2 7.72 0.02 (stat) 0.54 (syst) ? 1018 y
4.57 kg.y
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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100Mo 2?2? Single Energy Distribution
Single electron spectrum different between SSD
and HSD
Simkovic, J. Phys. G, 27, 2233, 2001
Esingle (keV)
NEMO-3
4.57 kg.y E1 E2 gt 2 MeV
4.57 kg.y E1 E2 gt 2 MeV
NEMO-3
2?2? SSD Monte Carlo
2?2? HSD Monte Carlo
SSD Single State
HSD higher levels
Background subtracted
Background subtracted
?2/ndf 139. / 36
?2/ndf 40.7 / 36
Esingle (keV)
Esingle (keV)
HSD T1/2 8.61 0.02 (stat) 0.60 (syst) ?
1018 y SSD T1/2 7.72 0.02 (stat) 0.54
(syst) ? 1018 y
100Mo 2?2? single energy distribution in favour
of Single State Dominant (SSD) decay
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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2?2? preliminary results for other nuclei
NEMO-3
Background subtracted
932 g 241.5 days 2385 events S/B 3.3
82Se
82Se T1/2 10.3 0.2 (stat) 1.0 (syst) ?
1019 y 116Cd if SSD T1/2 2.8 0.1 (stat)
0.3 (syst) ? 1019 y if HSD T1/2
3.05 0.1 (stat) 0.3 (syst) ? 1019 y 150Nd
T1/2 9.7 0.7 (stat) 1.0 (syst) ? 1018
y 96Zr T1/2 2.0 0.3 (stat) 0.2
(syst) ? 1019 y

• Data

bb2n simulation
E1E2 (keV)
NEMO-3
NEMO-3
NEMO-3
37 g 168.4 days 449 events S/B 2.8
5.3 g 168.4 days 72 events S/B 0.9
405 g 168.4 days 1371 events S/B 7.5
96Zr
150Nd
116Cd
bb2n simulation
bb2n simulation
bb2n simulation
E1E2 (MeV)
E1E2 (MeV)
E1E2 (MeV)
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris
14-19 June 2004
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Search for 2b0n decay in NEMO-3
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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bb0n Analysis Background Measurement
NEMO-3 can measure each component of its
background !
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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bb0n Analysis Background Measurement
Radon in the NEMO-3 gas of the wire chamber
Due to a tiny diffusion of the radon of the
laboratory inside the detector A(Radon) in the
lab 15 Bq/m3
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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bb0n Analysis with 100Mo
100Mo
2.6ltE1E2lt3.2
2.8ltE1E2lt3.2
1.4 ? 0.2
32.3 ? 1.9
100Mo 2b2n M-C
5.6 ? 1.7
23.5 ? 6.7
Radon M-C
7.0 ? 1.7
55.8 ? 7.0
TOTAL Monte-Carlo
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DATA
V-A T1/2(bb0n) gt 3 1023 y VA
T1/2 gt 1.8 1023 y with ?E1-
E2?gt 800 keV Majoron T1/2 gt 1.4 1022 y
with Esingle gt 700 keV
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004
Paris 14-19 June 2004
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100Mo bb0n likelihood analysis

• 3 variables used for the likelihood
• Ec1 Ec2 sum of the kinetic energies of the 2
  e-
• Ecmin energy of the e- of minimal energy
• Cos? angle between the two tracks

Ec Energy at the exit of the 100Mo foil
Energy deposited in scintillator (E)
energy losses in the tracking detector
!
Nbb0n
xbb0n is the free parameter
Ntot
L calculated with bb events Ec1Ec2gt2 MeV
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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100Mo bb0n likelihood analysis
100Mo 6914 g 216.4 days 4.10 kg.y
Ec1Ec2 (keV)
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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82Se bb0n likelihood analysis
PRELIMINARY
82Se 932 g 216.4 days 0.55 kg.y
82Se 932 g 216.4 days 0.55 kg.y
Ec1Ec2 (keV)
Ec1Ec2 (keV)
V-A T1/2(bb0n) gt 1.9 1023 y (90 C.L.)
VA T1/2 gt 1.0 1023 y (90 C.L.)
Majoron T1/2 gt 1.2 1022 y (90 C.L.)
Previous limit V-A T1/2(bb0n) gt 9.5 1021 y
(NEMO-2) Arnold et al. Nucl. Phys. A636 (1998)
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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Limit on the effective mass of the Majorana
neutrino, on Majoron and on VA
Limits on T1/2 are _at_ 90 C.L.
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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Free-Radon Purification System in construction
Today Radon is the dominant background for NEMO-3
Today A(222Rn) in the LSM 15 Bq/m3
Factor 10 too high
May 2004 Tent surrounding the detector
May 2004
August 2004 Radon-free SuperKamiokande-like
Air Factory Expected activity A(222Rn) 0.2
Bq/m3 150 m3/h 500 kg charcoal _at_ -40oC
Expected Purification Factor 75
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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NEMO-3 Expected sensitivity (after Radon
purification)

• Background
• External Background is negligible
• Internal Background
• 208Tl 100 mBq/kg for 100Mo
• 300 mBq/kg for 82Se
• 214Bi lt 300 mBq/kg
• 0.1 count kg-1 y -1 with
  2.8ltE1E2lt3.2 MeV
• bb2n T1/2 7.7 1018 y (SSD)
• 0.3 count kg-1 y -1 with
  2.8ltE1E2lt3.2 MeV

5 years of data 6914 g of 100Mo
T1/2(bb0n) gt 4 .1024 y (90 C.L.) ltmngt lt
0.2 0.35 eV 932 g of 82Se T1/2(bb0n) gt 8
.1023 y (90 C.L.) ltmngt lt 0.65 1.8 eV
(conservative limit)
Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004
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CONCLUSIONS

• NEMO-3 Detector running since 14 Feb. 2003
• Expected performance of the detector has been
  reached !
• 2b2n preliminary results for 100Mo, 82Se, 96Zr,
  116Cd and 150Nd
• already more than 140 000 2b2n events
  collected
• 100Mo in favour of Single State
  Dominance (SSD)
• 100Mo bb2n decay to excited state has
  been measured with 4 s
• Preliminary T1/2(bb0n) limit (216.4 days of
  data)
• 100Mo (4.10 kg.y) T1/2(bb0n) gt 3.5 1023 y
  ? ?mn? lt 0.7 1.2 eV
• 82Se (0.55 kg.y) T1/2(bb0n) gt 1.9 1023 y
  ? ?mn? lt 1.3 3.6 eV
• Level of backgounds as excepted except Radon
  10 times too high
• Free radon purification system in operation in
  August 2004
• Supression factor 75
• Expected sensitivity in 5 years after radon
  purification
• 100Mo T1/2(bb0n) gt 4 .1024 y ltmngt lt
  0.2 0.35 eV
• 82Se T1/2(bb0n) gt 8 1023 y ltmngt lt
  0.65 1.8 eV

Xavier Sarazin for the NEMO-3 Collaboration
Neutrino 2004 Paris 14-19 June
2004