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Double beta decay study at LNGS (the experiments CUORE and CUORE-0)

Lucifer. made in the frame of LUCIFER experiment FP7/2007-2013 ERC grant agreement n. 247115. XXIV SEMINARIO NAZIONALE di FISICA NUCLEARE E SUBNUCLEARE OTRANTO, Serra degli Alimini, 21-27 Settembre 2012 Argomento : Studio del decadimento doppio beta ai LNGS

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Double beta decay study at LNGS (the experiments CUORE and CUORE-0)

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  1. Lucifer made in the frame of LUCIFER experiment FP7/2007-2013 ERC grant agreement n. 247115. XXIV SEMINARIO NAZIONALE di FISICA NUCLEARE E SUBNUCLEARE OTRANTO, Serra degli Alimini, 21-27 Settembre 2012 Argomento: Studio del decadimento doppio beta ai LNGS Lezione 2: Esperimento CUORE Double beta decay study at LNGS(the experiments CUORE and CUORE-0) I. Dafinei Università "La Sapienza" di Roma and Sezione INFN - Roma

  2. double beta decay study at LNGS cryogenic bolometers; insights CUORE and CUORE-0 experiments Outline

  3. 0νDBD (claimed evidence!) neutrino physics 0νDBD DBD LNGS in a glance past experiments

  4. neutrino physics 0νDBD DBD LNGS in a glance current experiments:

  5. LNGS in a glance current experiments: GERDA–76Ge Array of enriched Ge diodes operated in liquid argon First phase: 18 Kg; second phase: 40 Kg - LNGS Proved energy resolution: 0.2 % FWHM CUORE–130Te Array of low temperature natural TeO2 calorimeters operated at 10 mK First step: 200 Kg (2014) – LNGS – it can take advantage from Cuoricino experience Proved energy resolution: 0.2 % FWHM LUCIFER–82Se – 116Cd – 100Mo Array of scintillating bolometers operated at 10 mK (ZnSe or ZnMoO4 or CdWO4) First step: ~ 10 Kg (2014) – LNGS – essentially R&D project to fully test the principle Proved energy resolution: 0.3 –0.7 % FWHM

  6. (more about) LNGS merits • LNGS (underground facility) • position: latitude 42°27'N, longitude 13°34'E • average depth: 3800 m of water equivalent (m.w.e.) • minimum depth: 3000 m.w.e. • altitude: 963 m above sea level • intensity of charged cosmic rays reduced 106 times with respect to the flux at the surface (~1muon·m-2·h-l; energy threshold 2 TeV). • reduced neutrons flux due to spontaneous fission in the rocks • ~3×10-6cm-2s-1 (thermal neutrons) • <0.3×10-6cm-2s-1 (fast neutrons) • (three orders of magnitude less than at the surface) • background due to gamma rays similar or higher than in a surface laboratory due to the radioactivity of the rocks and concrete which cover the halls (problem easily solved by proper shielding)

  7. background gamma spectra measured with Ge detector with proper shielding Milano LNGS (more about) LNGS merits typical HPGe spectrum in hall C • radionuclides: • of natural radioactive series (226Ra, 214Bi, 214Pb 238Ac, 224Ra, 208Tl, 212Pb and the Actinium series) • long-lived natural (40K, 87Rb, 115In, 133La, 142Ce, etc.) • of cosmogenic origin (3H, 7Be, 14C, 22Na, 26Al, 60Co) • of artificial origin (long-lived fission products like 95Nb, 95Zr, l44Ce, l06Ru, 134Cs, 125Sb, 137Cs, etc.) C. Arpesella, Appl. Radiat. Isot. 47, 9/10 (1996), 991

  8. energy resolution LTD scintillator gas detector solid state detectors : 100 eV  30 eV  3 eV  < 0.01 eV (more about) cryogenic bolometers advantages energy threshold much lower than in conventional devices sensitivity to non-ionizing events large choice for energy absorber materials possible discrimination of interacting particle

  9. (more about) cryogenic bolometers largest (2.1kg) bolometer ever operated FWHM= 7.8 keV

  10. all the particle energy is converted into phonons, producing a crystal temperature variation of ~0.1 mK/MeV crystal heating changes the thermistor resistance of ~3MΩ/MeV determining a voltage variation of ~0.3 mV/MeV FWHM resolution ~ 5 keV @0νDBD (2528 keV) 2b - 2.528MeV CUORE CUORE in a glance • 19 towers containing 134=52 detectors each • 988 TeO2 crystals (5x5x5 cm3) • total detector mass: 741 kg • total 130Te mass: 206 kg (natural abundance)

  11. detector suspension support CUORE dilution unit pulse tube remote motor pulse tube head top Pb shield lateral Pb shield CUORE detector how? • dilution refrigerator (Leiden Cryogenics) • detector suspensions independent • minimum lead thickness ~ 36 cm • strict radiopurity controls • materials • assembly 11

  12. CUORE Hut Cuoricino Hut CUORE where? 12

  13. CUORE the hut, now 13

  14. CUORE CUORE-0 • 52 CUORE crystals mounted in CUORE-style frames as a single tower (39 kg TeO2) • assembled from detector components manufactured, cleaned and stored following the same protocols defined for CUORE • to be operated in the Cuoricino cryostat • expected to surpass Cuoricino performance 14

  15. CUORE Cartesian robot for glue dosing Anthropomorphous robot for sensors and crystals handling CUORE-0 sensor-to-crystal connections 15

  16. CUORE CUORE-0 sensor-to-crystal connections 16

  17. CUORE precise and uniform gluing CUORE-0 sensor-to-crystal connections 17

  18. Tower can be conveniently lifted up and down CUORE Universal Working Plane Tower Garage Clean Room Floor CUORE-0 CUORE Tower Assembling Line (CTAL) • single assembly station (4 interchangeable glove boxes) • mechanics • wiring/shielding • bonding • storage • zero contact system • (controlled nitrogen atmosphere) 18 18

  19. MechBox CUORE CUORE-0 CUORE Tower Assembling Line (CTAL) • single assembly station (4 interchangeable glove boxes) • mechanics • wiring/shielding • bonding • storage • zero contact system • (controlled nitrogen atmosphere) 19 19

  20. CablingBox CUORE CUORE-0 CUORE Tower Assembling Line (CTAL) • single assembly station (4 interchangeable glove boxes) • mechanics • wiring/shielding • bonding • storage • zero contact system • (controlled nitrogen atmosphere) 20 20

  21. BondingBox CUORE CUORE-0 CUORE Tower Assembling Line (CTAL) • single assembly station (4 interchangeable glove boxes) • mechanics • wiring/shielding • bonding • storage • zero contact system • (controlled nitrogen atmosphere) 21 21

  22. StorageBox CUORE CUORE-0 CUORE Tower Assembling Line (CTAL) • single assembly station (4 interchangeable glove boxes) • mechanics • wiring/shielding • bonding • storage • zero contact system • (controlled nitrogen atmosphere) 22 22

  23. CUORE CUORE-0 assembling 23 23 23

  24. CUORE CUORE-0 wiring 24

  25. CUORE CUORE-0 wiring 51/52 NTD successfully bonded 25

  26. CUORE CUORE-0 shielding 26

  27. CUORE CUORE-0 shielding 27

  28. CUORE CUORE-0 shielding 28

  29. acknowledgements this work was made in the frame of LUCIFER experiment funded by the European Research Council under the European Unions Seventh Framework Programme FP7/2007-2013 / ERC grant agreement n. 247115.

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