Stefano Torre University College London for NEMO3 and SuperNEMO collaborations Half day IoP Meeting 12 Oct 2011 Outline 0νββ and 2νββ Observation technique Nemo-3 Results SuperNEMO design and construction Double beta decay with NEMO3 and SuperNEMO

2 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Which process cause the double beta decay? But η can be due to mass mechanism, V+A, majoron, SUSY,... with different topology in the final state  - angle between e 1 and e 2 E 1 - single e - energy, keV 〈mν〉〈mν〉 V+A

3 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Measuring the Lepton Violating parameter Isotope Q ββ, MeV 48 Ca Ge Se Zr Mo Cd Te Xe Nd 3.37 G 0ν × yr , Phase space factor phase space is known half life is measured need to know the Nuclear Matrix Element (NME) variation between models and Isotopes combine measurement from as many isotopes as possible

4 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 NEMO3 ββ isotope foils PMT cathode rings wire chamber Plastic scintillator use calorimeter for energy and time measurement use tracker for full event reconstruction identify e -, e +, ɣ, α 10 kg of ββ isotopes: 7kg 100 Mo 1kg 82 Se smaller quantities of 116 Cd, 150 Nd, 48 Ca, 96 Zr, 130 Te

5 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 NEMO3 source distributed on cylindrical surface drift wire chamber operated in geiger mode (6180 cells) He + 4% ethyl alcohol + 1% Ar + 0.1%H 2 O calorimeter made of 1940 plastic scintillators coupled to low radioactivity PMTs Magnetic field: 25 Gauss Gamma shield: iron Neutron shield: 30cm borated water (external wall) 40cm wood (top and bottom)

6 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 NEMO3 LSM Modane, France (Tunnel Frejus, depth of ~4,800 mwe )

7 Selection of ββ events S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 foil of 100 Mo vertex scintillator track vertex Run : 3478 Event: 6930 Date: 09/11/2004 (Δvertex)  = 3 cm 2 tracks with charge < 0 2 PMT, each > 200 keV PMT-Track association Common vertex Internal hypothesis (external event rejection) No other isolated PMT (γ rejection) No delayed track ( 214 Bi rejection) Criteria to select ββ events 1 ββ event every 2,5 minutes Top viewSide view

8 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Backgrounds External Internal Background measurement in NEMO-3: NIM A606 (2009) 449 Natural radioactivity 238 U, 232 Th, 40 K, Rn Cosmics neutrons

9 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Background: Rn activity Measurements of 222 Rn activity in the gas of tracker (mBq/m 3 ) T 1/2 = 162.9μs Delay time of the α track (μs) 214 Bi → 214 Po (164 μs) → 210 Pb

10 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/ two-electron events from 100 Mo foils S/B = 76 ε(2ν2β) = T 1/2 (2ν2β) = [ (stat)] y PRELIMINARY To be compared with the published NEMO-3 result obtained with Phase 1 data T 1/2 = [ (stat) (syst)] y Phys.Rev.Lett. 95(2005) Mo evts S/B=40 Phase 1 NEMO-3 2νββ 100 Mo Phase 2 data, 4 years

11 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 2νββ Results IsotopeMass (g)Q ββ (keV)T 1/2 (2ν) (10 19 yrs)CommentReference 82 Se ± 1.0World’s best! 116 Cd ± 0.3World’s best! 150 Nd ± 0.07World’s best! Phys. Rev. C 80, (2009) 96 Zr ± 0.21World’s first and best! Nucl.Phys.A 847(2010) Ca ± 0.6World’s best! 100 Mo ± 0.05World’s best! Phys.Rev.Lett. 95(2005) Te ± 14World’s first and best! Phys. Rev. Lett. 107, (2011) First direct observation Indirect observations: - ~2.7 x yrs in 10 9 yr old rocks - ~8 x10 20 yrs in yr old rocks Indication from MIBETA Coll in isotopically enriched crystals: 6.1 ± 1.4(st) (sy) x10 20 yrs

12 Search for 0νββ S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Total mean 0ν efficiency ε = Se T 1/2 (0ν) > C.L. < 0.94 – 1.71 eV NME [1-4] < 2.6 eV NME [6] Total mean 0ν efficiency ε = Mo T 1/2 (0ν) > C.L. < 0.31 – 0.96 eV NME [1-5] [1] QRPA M.Kortelainen and J.Suhonen, Phys.Rev. C 75 (2007) (R) [2] QRPA M.Kortelainen and J.Suhonen, Phys.Rev. C 76 (2007) [3] QRPA F.Simkovic, et al. Phys.Rev. C 77 (2008) PHFB [5] P.K. Rath et al., Phys. Rev. C 82 (2010) [4] IBM2 J.Barrea and F.Iachello Phys.Rev.C 79(2009) SM [6] E.Caurrier et al. Phys.Rev.Lett 100 (2008) NME 82 Se 100 Mo 100 Mo : 7kg × 4.5 years 82 Se : 1kg × 4.5 years

13 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 n: spectral index, limits on half-life in years * Phase I+Phase II data (including 2008) ** Phase I data, R.Arnold et al. Nucl. Phys. A765 (2006) 483 Majoron emission would distort the shape of the energy sum spectrum V+A*n=1n=2**n=3**n=7** Mo > 5.7∙10 23 λ<1.4∙10 -6 > 5.3∙10 22 G ee <( )∙10 -4 > 1.7∙10 22 > 1.0∙10 22 > 7∙10 19 Se > 2.4∙10 23 λ  2.0∙10 -6 > 1.5∙10 22 ** G ee <( )∙10 -4 > 6∙10 21 > 3.1∙10 21 > 5∙10 20 Preliminary

14 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/ th January 2011: So long NEMO3

15 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 From NEMO to SuperNEMO Isotope mass M Isotope Contaminations in the ββ foil Calorimeter energy resolution (FWHM) 7 kg 100 Mo NEMO Tl: ~ 100 μBq/kg 214 Bi: < 300 μBq/kg Rn: 5 mBq/m 3 T 1/2 (ββ0ν) > 1÷2 x y < 0.3 – 0.9 eV 3MeV 100+ kg 82 Se (or 150 Nd or 48 Ca) SuperNEMO 208 Tl ≤ 2 μBq/kg 214 Bi ≤ 10 μBq/kg Rn ≤ 0.15 mBq/m 3 T 1/2 (ββ0ν) > 1 x y < eV 3 MeV Rn in the tracker Sensitivity R&D since 2006

16 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 SuperNEMO Modular design 20 modules, each with 5kg of isotope Each Module: Source: (40mg/cm 2 ) 4x2.7m 2 82 Se (High Q ββ, long T 1/2 (2ν), proven enrichment technology) 150 Nd, 48 Ca being looked at Tracking drift chamber ~2000 cells in Geiger mode Calorimeter: 550 PMTs + scintillators Module surrounded by water and passive shielding Source 2.7m Submodule tracker Submodule calorimeter Submodule Source and calibration 6 m 4 m 2 m (assembled, ~0.5m between source and calorimeter)

17 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Main calorimeter walls design ΔE/E ~ 7.2% (FWHM) at 1 MeV equiv. to Q ββ = 3 MeV Required resolution has now been reached on hexagonal as well as cubic blocks

18 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 X-walls R&D and construction Resolution: ~ 1Mev Use scintillators on the side of tracker (X-wall) for event reconstruction increase acceptance on signal and SuperNEMO sensitivity if resolution 3∙10 25 yr for 76 Ge ~ 6.5∙10 24 yr for 82 Se

19 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Tracker R&D Basic design developed and verified with several prototypes Resolution: 0.7mm transverse, 1cm longitudinal Cell efficiency > 98% Automated wiring robot design to mass produce at ultra low background condition Readout electronic being developed right now: Allow for single and double cathodes readout Differentiate anode signal

S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011   (164  s) 238 U 214 Bi (19.9 mn) 210 Tl (1.3 mn) 214 Po 210 Pb 22.3 y 0.021%   (300 ns) 232 Th 212 Bi (60.5 mn) 208 Tl (3.1 mn) 212 Po 208 Pb (stable) 36% 82 Se source radiopurity shaped in foils of mg/cm 2 radio purity 208 Tl < 2 µBq/kg 214 Bi < 10 µBq/kg dedicated BiPo detector developed and installed in Canfranc

21 Radon Detector (Electrostatic & Pin Diode) S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Rn activity measurement Vacuum Pump Carbon Trap Radon Concentration Line sensitivity < 0.1 mBq/m 3

22 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 The Demonstrator of the technology of the control of background levels less than 0.2 background events in MeV with 21 kg yr (7kg×3yrs) to produce competitive result: reach NEMO3 ( 100 Mo) sensitivity in 4.5 months reach Gerda-I sensitivity by 2015 if good it will be the first SuperNEMO module

23 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Schedule Installation in LSM Demonstrator Module construction and commissioning Demonstrator Module running. “Klapdor” sensitivity end of 2015 Construction and deployment of successive SuperNEMO modules Continuous operation of ≥1 SuperNEMO module

24 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Conclusions NEMO3 has finished data taking no evidence of lepton violating decays has been found the double beta decay of seven isotopes has been measured analysis of final samples is currently ongoing SuperNEMO design is now being finalized the Demonstrator has now entered the construction phase

25 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Backup

26 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 Th and U chains

27 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 [2.8, 3.2] MeV: ε(0ν) = Tot MC= , Data: 6 events MC 2vbb = MC radon = MC int bkg= ( 214 Bi=0.1, 208 Tl=0.7) [2.8, 3.2] MeV: ε( 0 ν) = Tot MC= , Data: 12 events MC 2vbb = MC radon = MC int bkg= ( 214 Bi=0.4, 208 Tl=2.3) [2.8,3.2]MeV in 4.5 years 18 events observed, expected Search for 0νββ with 100 Mo

28 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 [2.6, 3.2] MeV: ε( 0 ν) = Tot MC= , Data: 4 events MC 2vbb = MC radon = MC int bkg= ( 214 Bi=0.55, 208 Tl=0.42) [2.6, 3.2] MeV: ε( 0 ν) = Tot MC= , Data: 10 events MC 2vbb = MC radon = MC int bkg= ( 214 Bi=2.2, 208 Tl=1.6) [2.6,3.2]MeV in 4.5 years 14 events observed, expected Search for 0νββ with 82 Se

29 S.Torre - Double beta decays with NEMO3 and SuperNEMO - 12/10/2011 [9.6±0.1(stat)±1.0(sys)]×10 19 y [ (stat)±0.63(sys)]×10 18 y Phys. Rev. C 80, (2009) [2.35±0.14(stat)±0.16(sys)]×10 19 y Nucl.Phys.A 847(2010)168 [2.88±0.04(stat)±0.16(sys)]×10 19 y [ (stat)±0.4(sys)]×10 19 y 82 Se 130 Te 116 Cd 96 Zr 150 Nd Preliminary [7.0±0.9(stat)±1.1(sys)]×10 20 y Phys. Rev. Lett. 107, (2011) 2νββ Results