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Probing neutrino mass with SuperNEMO

Probing neutrino mass with SuperNEMO. Ruben Saakyan Ulisse at LSM Workshop 30 June 2008. Outline. The Concept The Detector Physics reach Status of design study Schedule Summary. Neutrinoless double beta decay ( 0nbb ). D L = 2!. Lepton number violation parameter.

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Probing neutrino mass with SuperNEMO

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  1. Probing neutrino mass withSuperNEMO Ruben Saakyan Ulisse at LSM Workshop 30 June 2008

  2. Outline • The Concept • The Detector • Physics reach • Status of design study • Schedule • Summary R. Saakyan: Ulisse at LSM Workshop.

  3. Neutrinoless double beta decay (0nbb) DL = 2! Lepton number violation parameter can be due to , V+A, Majoron, SUSY, H-- or a combination of them! Need detectors which can probe different mechanisms (and different isotopes) R. Saakyan: Ulisse at LSM Workshop.

  4. SuperNEMO experimental technique M . t e A ln2 . N kC.L. (y) > . . NBkg . DE M: masse (g) e : efficiency KC.L.: Confidence level N: Avogadro number t: time (y) NBckg: Background events (keV-1.g-1.y-1) DE: energy resolution (keV) Focus on lowering Nbkg and open-minded search for any lepton violating process Calorimetry + Tracking • Build on NEMO3 experience • Reconstruct two electrons in the final state (E1+E2 = Qbb) • Measure several final state observables • Individual electron energies • Electron trajectories and vertices • time of flight • Angular distribution between electrons • Background rejection through particle ID: e-, e+, a, g • Sources separated from detector  can measure different isotopes R. Saakyan: Ulisse at LSM Workshop.

  5. From NEMO-3 to SuperNEMO SuperNEMO NEMO-3 82Se or/and 150Nd isotope 100Mo isotope massM 100-200 kg 7 kg 208Tl mBq/kg if 82Se: 214Bi  10 mBq/kg 208Tl: < 20 mBq/kg 214Bi: < 300 mBq/kg internal contaminations 208Tl and 214Bi in the bb foil energy resolution (FWHM) 8% @ 3MeV 4%@ 3 MeV T1/2(bb0n) > 2 x 1024 y <mn> < 0.3 – 0.9 eV T1/2(bb0n) > (1-2) x 1026 y <mn> < 0.04 - 0.11 eV Me Tobs NA T1/2 (bb0n) > ln 2   A N90 efficiency  ~ 30 % 18 % R. Saakyan: Ulisse at LSM Workshop.

  6. SuperNEMO Collaboration ~ 90 physicists, 12 countries, 27 laboratories Japan U Saga KEK U Osaka Marocco Fes U USA MHC INL U Texas Russia JINR Dubna ITEP Mosow Kurchatov Institute UK UCL U Manchester Imperial College Finland U Jyvaskula Poland U Warsaw Ukraine INR Kiev ISMA Kharkov France CEN Bordeaux IReS Strasbourg LAL ORSAY LPC Caen LSCE Gif/Yvette Slovakia (U. Bratislava) Spain U Valencia U Saragossa U Barcelona Czech Republic Charles U Praha IEAP Praha R. Saakyan: Ulisse at LSM Workshop.

  7. SuperNEMO preliminary design Planar geometry. 20 modules for 100+ kg Single model (baseline design) Source (40 mg/cm2) 12m2 , tracking volume (~2k Geiger channels). calorimeter (600 channels) Total: ~ 40 Geiger channels for tracking ~ 12k PMTs (3k if scintillator bars design) 4 m 1 m 5 m Top view Side view R. Saakyan: Ulisse at LSM Workshop.

  8. Single sub-module with ~5-7 kg of isotope ~20 sub-modules for 100+ kg of isotope surrounded by water shielding R. Saakyan: Ulisse at LSM Workshop.

  9. LSM hall A Moving out a module 1,5m 1m Realistic module mass : 14-19t 4,1m 7,75m 1,5m 2,4m J.FORGET SuperNEMO general design june 2008 1,5m R. Saakyan: Ulisse at LSM Workshop.

  10. N LSM hall A Allocated surfaces 100m 62m 46m 12m 10m 15m He storage ISO6 workshop Up to 30 modules 135 kg 82Se 17,5m 24,5m Heavy work surface Radonless air and gaz mixtures production 22 modules 100 kg 82Se R. Saakyan: Ulisse at LSM Workshop.

  11. Choice of Isotope • Criteria of choice: • High Qbb value • Phase space G0n • 2nbb half-life • natural abundance • enrichment possibilities • purification of 4kg of 82Se underway • (INL, US) • enrichment of 150Nd possible 82Se obtained by centrifugation Impossible for 150Nd, only laser enrichment R. Saakyan: Ulisse at LSM Workshop.

  12. SuperNEMO simulations • Full detector simulation • Event generator GENBB (bb + radioactivity) • Geant 4 • Reconstruction • Tracks reconstructed from tracker hits and fitted • Cellular automation for track patterns • Kalman filter for fitting • Even vertex found in the foil • Track matched with calorimeter hits • Charge sign measured from curvature • Draws heavily from NEMO3 experience SNOVA Overall efficiency ~30% (conservative scenario: B-field on, module width 1m, reject “double hits” etc..) R. Saakyan: Ulisse at LSM Workshop.

  13. SuperNEMO simulations and physics reach Se82 Nd150 “Conservative” scenario Sensitivity 82Se: T1/2(0n) =(1-2) 1026 yr depending on final mass, background and efficiency <mn>  0.06 – 0.1 eV (includes uncertainty in T1/2) – MEDEX’07 NME 150Nd: T1/2(0n) =5 1025 yr <mn>  0.045 eV (but deformation not taken into account) R. Saakyan: Ulisse at LSM Workshop.

  14. SuperNEMO Design Study 2006 – 2009 • Approved in UK, France and Spain. Smaller but vital contributions from US, Russia, Czech Republic, Japan. • Main tasks and deliverables • R&D on critical components • Calorimeter energy resolution of 4% (FWHM) at 3 MeV • Optimisation of tracking detector and construction (robot) • Better background rejection (e.g. extra veto counters) • Ultra-pure source production and purity control • Simulations and geometry optimisation. • Technical Design report in 2010 • Experimental site selection (Frejus, Canfranc, Gran Sasso, Boulby) R. Saakyan: Ulisse at LSM Workshop.

  15. Calorimeter R&D Factor of 2 compared to NEMO3! • Energy resolution is a combination of energy losses in foil and calorimeter DE/E • Goal: 7-8%/√E  4% at 3 MeV (82Se Qbb) • Studies: • Material: plastic (PST, PVT) or liquid • Geometry and shape (blocks, bars) • Size • Reflective coating • PMT • High QE • Ultra-low background R. Saakyan: Ulisse at LSM Workshop.

  16. Calorimeter R&D. & DE/E = 6.5% at 1 MeV  3.8% at 3 MeV 207Bi Hamamatsu high-QE PMT scintillator Scint. Block in dark box DAQ 90Sr (370 MBq) e- beam trigger R. Saakyan: Ulisse at LSM Workshop.

  17. Calorimeter R&D. Results so far. Solid Scint. Results ** preliminary Baseline design target! R. Saakyan: Ulisse at LSM Workshop.

  18. Calorimeter R&D. Results so far. Liquid Scint. Results R. Saakyan: Ulisse at LSM Workshop.

  19. Calorimeter R&D. Status. • Four routes pursued • 8” PMT + plastic block • 8” PMT + liquid scintillator • 8” PMT + hybrid (liquid + plastic) scintillator • 2m scint. bar with 3” or 5” PMTs • Target resolution 7-8% at 1 MeV (~4% FWHM at 3 MeV) reached for individual large baseline design blocks. • PMTs • Working closely with manufacturers: Hamamatsu, Photonis, ETL • Real breakthrough in high-QE PMTs from Hamamatsu and Photonis: 43% QE. • Deep involvement in ultra-low background PMT development (especially Photonis) • Decision on calorimeter design in early 2009 R. Saakyan: Ulisse at LSM Workshop.

  20. Tracker R&D Optimize length, wire material and diameter, read-out, gas mixture etc Several 1-cell and two 9-cell prototypes built and tested 90-cell prototype being built 9-cell prototype in Manchester R. Saakyan: Ulisse at LSM Workshop.

  21. Tracker studies. 1-cell prototypes. - Wire diameter studies - Anode vs cathode rings only readout for longitudinal position reconstruction (anode readout feasible) - Electron drift times measured with laser - Cell diameter studies 370 cm - Transverse position from electron drift times - Longitudinal position from plasma propagation times Plasma propagation times Anode and cathode ring signals from ionization event R. Saakyan: Ulisse at LSM Workshop.

  22. Tracker studies. 9- and 90-cell prototypes. 9-cell: End-cap design optimized for wiring robot feasible 8-12 wires per cell work Geiger plateau > 200 V Plasma propagation efficiency ~100% 90-cell Will be built and wired by August Tracking efficiency, cross-talk, ageing etc Final SuperNEMO tracker design in early 2009. 12 wires per cell 8 wires per cell R. Saakyan: Ulisse at LSM Workshop.

  23. Actuator mechanism Clamp mechanism Pair of end fittings Anode wire feed mechanism Tracker fully automated wiring. Up to ~500,000 wires to be strung, crimped, terminated Wiring robot being developed in collaboration with Mullard Space Science Lab (UCL) R. Saakyan: Ulisse at LSM Workshop.

  24. BiPo detector • To measure contaminations of 208Tl and 214Bi in source foils before installation in SuperNEMO • Goal: ~5kg of foil (12m2 , 40mg/cm2) in one month with a sensitivity of • 208Tl < 2 mBq/kg • 214Bi < 10mBq/kg Background < 1 event/month! • BiPo-1 to measure scintillator surface contamination • Installed and commissioned in Canfranc in October’07 • Temporarily relocated to Modane until Canfranc reopens • Extrapolated sensitivity from BiPo-1 first results:~1-10 mBq/kg • BiPo-2 results expected end 2008. R. Saakyan: Ulisse at LSM Workshop.

  25. Schedule Summary 2010 2011 2007 2008 2009 2012 2013 BiPo construction 2014 ? NEMO3 Running SuperNEMO Design Study BiPo1 Canfranc/LSM BiPo installation BiPo running @ Canfranc SuperNEMO 1st module construction Preparation of new LSM site construction of 20 modules 1-4 SuperNEMO modules running at Canfranc Running full detector in 2014 Target sensitivity (0.05-0.1 eV) in 2016/17 Installation at new LSM R. Saakyan: Ulisse at LSM Workshop.

  26. Summary • SuperNEMO: a chance to see a “smoking gun” evidence for 0nbb and directly disentangle underlying physics mechanism (V+A, Majoron, etc) • Design Study addresses most critical issues • Energy resolution • Tracker optimization • Radiopurity • Based on design study results full proposal for 100+ kg detector in 2010. • 82Se – baseline, 150Nd possible. • “Last minute” isotope change if e.g. CUORE sees the signal in 130Te. • Start-up in stages due to modular approach • First module 2010/11 • All 20 modules ~2013 • Target sensitivity: 50-100 meV by 2016/17 R. Saakyan: Ulisse at LSM Workshop.

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