Nemo 3 and Supernemo experiments Neutrinoless  decay


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NEMO 3 and SuperNEMO experiments


Neutrinoless  decay



NEMO-3 detector





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 eevents from foil.
    • decay


Radon free air facility



results for 100Mo



results for 82Se



decay for other isotopes



Exotic processes search

  • V+A current in electroweak lagrangian

  • Neutrino coupled axions  (majorons)



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



Modular design



Alternative design (bar scintillator)



Calorimeter R&D so far



Wiring robot



BiPo device, ultra low purity msr.



Isotope choice



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.







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