370 likes | 525 Views
Search for neutrinoless double beta decay with NEMO 3 and SuperNEMO experiments. Vladimir Vasiliev UCL, London, UK on behalf of the NEMO collaboration. SUSY 2007 Karlsruhe, 28 July 2007. bb decay, n mass mechanism. predicted in 1935 by Maria Goeppert-Mayer.
E N D
Search for neutrinoless double beta decay with NEMO 3 and SuperNEMO experiments Vladimir Vasiliev UCL, London, UK on behalf of the NEMO collaboration SUSY 2007 Karlsruhe, 28 July 2007
bb decay, n mass mechanism predicted in 1935 by Maria Goeppert-Mayer DL = 2 - only possible for Majorana neutrinos with mass > 0 Beyond the SM: Lepton Number Violation ! 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 2
bb decay and SUSY: R-parity breaking dR+dR → uL+uL+eL+eL exchange with: squarks neutralinos gluinos related to (l'111)2 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 3
bb decay and SUSY: squark mixing dR+dR → uL+uL+eL+eL Mixing between L- and R- handed fermion superpartners. Paes, Hirsch,Klapdor-Kleingrothaus, PLB 459(1999) 450 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 4
bb decay and SUSY: neutrino mass dR+dR → uL+uL+eL+eL neutrino acquires mass due to SUSY radiactive corrections Gozdz, Kaminski, Šimkovic, PRD 70 (2004) 095005 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 5
bb decay mechanism • If observed, how to determine mechanism: nmass, SUSY, V+A ... ??? • measure kinematical parameters: angular correlation, individual electron energy! • measure several isotopes! • measure bb0n decay to excited state of final nuclei! Calorimetry plus tracking approach: Detection of both electrons, three kinematic observables:individual electron energies; angular correlation; energy sum Sources separated from the detector:measure T½ for several isotopes Particle identification:e-, g; good signature for decay to excited states Unique and complementary 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 6
20 sectors B(25 G) 3 m 4 m key techniques: tracking, calorimetry, timing NEMO-3 • Goal: reconstruct 2 electrons of the final state • E1 + E2 = Qbb • Particle physics - like approach: • Measure several observables of the final state • Trajectories of 2 electrons • Energies of 2 electrons • Time • Magnetic field curvature ("+" vs "-") • Reconstruct the final state topology and kinematics • Several requirements for candidate events • Topology (vertex, track-scintillator correlation) • Time coincidence • 2-electron invariant mass • Identify e-, e+, g, a • Able to measure backgrounds 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 7
bb2n measurement bb0n search Multi source detector 116Cd405 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 130Te454 g Qbb = 2529 keV Detector bkg measurement natTe893 g 100Mo6.914 kg Qbb = 3034 keV 82Se0.932 kg Qbb = 2995 keV Cu621 g 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 8
Sector interior view cathode rings wire chamber PMTs Calibration tube scintillators bb isotope foils 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 9
Installation in Modane 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 10
Installation in Modane 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 11
With shielding water tank wood coil iron shield 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 12
Full detector now 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 13
Transverse view Run Number: 2040 Event Number: 9732 Date: 2003-03-20 Longitudinal view Vertex emission Vertex emission Deposited energy: E1+E2= 2088 keV Internal hypothesis: (Dt)mes –(Dt)theo = 0.22 ns Common vertex: (Dvertex) = 2.1 mm (Dvertex)// = 5.7 mm Typical bb2n event observed from 100Mo 100Mo6.914 kg Qbb = 3034 keV Criteria to select bb events: • 2 tracks with charge < 0 • 2 PMT, each > 200 keV • PMT-Track association • Common vertex • Internal hypothesis TOF (external event rejection) • No other isolated PMT (g rejection) • No delayed a track (214Bi rejection) 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 14
External double Compton Compton + Moller pair production Internal b- +Compton b- +Moller b- +IC NEMO backgrounds • Natural radioactivity: • U/Th chain • 40K • Rn • cosmic m • neutrons 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 15
Backgrounds: Radon purification facility Running since Oct. 4th, 2004 in FréjusUnderground Lab. 1 ton charcoal @ -50oC, 7 bars Flux: 150 m3/h Activity of 222Rn : Before Facility = 15 Bq/m3 After Facility < 15 mBq/m3 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 16
Radon purification facility, effect inside NEMO3 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 17
Backgrounds: bb-like events from Cu - background sources simulated using Monte Carlo - radioactivity rates from material tests in HPGe and control channel meas's Phase II data; ~ 1.5 y. MC prediction: 130 ev. 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 18
Angular distribution Sum energy spectrum 12000 10000 8000 6000 4000 2000 0 219 000 events 6914 g 389 days S/B = 40 219 000 events 6914 g 389 days S/B = 40 12000 10000 8000 6000 4000 2000 0 Number of events • Data 22 Monte Carlo • Data 22 Monte Carlo Background subtracted Background subtracted Cos() T1/2() = 7.11 0.02 (stat) 0.54 (syst) 1018 years « factory»→ tool for precision test NEMO 3 highlights: 2b2n100Mo NEMO-3 NEMO-3 100Mo 100Mo Number of events/0.05 MeV E1 + E2 (MeV) Phys. Rev. Lett. 95 182302 (2005) 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 19
48Ca NEMO 3 highlights: 2b2n preliminary Preliminary results for ~360 d Phase I data. Additional statistics is being analysed and to be published soon. 82Se T1/2 = 9.6 ± 0.3 (stat) ± 1.0 (syst) 1019 y 116Cd T1/2 = 2.8 ± 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 48Ca T1/2 = 3.9 ± 0.7 (stat) ± 0.6 (syst) 1019 y 932 g 389 days 2750 events S/B = 4 82Se Background subtracted 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 20
NEW in 2007: direct meas. of 130Te 2b2n • The half-life of 130Te has been a long-standing mystery:: • Geochemical: • (25 ± 2) x 1020 years (Kirsten 83) • (27 ± 2) x 1020 years (Bernatowicz 93) • (7.9 ± 1) x 1020 years (Takaoka 96) • ~8 x 1020 years (Manuel 91) • Difference between ‘old’ and ‘young’ ores due to • time dependence of constants..? • Ratio of 82Se/130Te (less systematics): • (9 ± 1) x 1020 years (average by A. Barabash) • Direct measurement: • (6.1 ± 1.4 (syst) ± 2.93.4) x 1020 years (Arnaboldi 2003) 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 21
NEW in 2007: direct meas. of 130Te 2b2n 109 events 607 events background subtracted 534 days, 454 g of 130Te 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 22
NEMO 3 highlights: 2b0n100Mo & 82Se 100Mo, Phase I + II, 693 days 82Se ,Phase I + II, 693 days T1/2 > 2.1 x 1023 (90 % CL) <mn>* < 1.4-2.2 eV l'111 < 2.5 10-4 T1/2 > 5.8 x 1023 (90 % CL) <mn>* < 0.8 – 1.3 eV l'111 < 1.5 10-4 T1/2 > 8 x 1023 (90 % CL) <mn>* < 0.7-1.1 eV expected in 2009: T1/2 > 2 x 1024 (90 % CL) <mn>* < 0.4 – 0.7 eV • Collaboration decided to perform blind analysis with mock data • Plan to open the box and update the results ~ summer 2008 and again ~ early 2010. * Recent QRPA NME calculation as in MEDEX'07 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 23
'Majoron' search Axions (‘Majorons’) with coupling to neutrinos best limits n: spectral index, limits on half-life in years ** PI data, R.Arnold et al. Nucl. Phys. A765 (2006) 483 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 24
SuperNEMO project 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 25
~ 60 physicists, 27 laboratories, 12 countries, Japan U Saga KEK U Osaka Marocco Fes U USA MHC INL (U Texas) Russia JINR Dubna ITEP Mosow Kurchatov Institute UK UC London 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 Zaragoza U Barcelona Czech Republic Charles U Praha IEAP Praha 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 26
1 module: Source (~40 mg/cm2) 4 (length) x 3(height) m2 Tracking : drift chamber ~3000 cells in Geiger mode Calorimeter: scintillators + PM ~1 000 PM if scint. blocks ~ 100 PM if scint. bars Very preliminary SuperNEMO design Planar and modular design: ~ 100 kg of isotope (~20 modules 5-7 kg) 4 m Top view 1 m 5 m 5 m 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 27
Very preliminary SuperNEMO design Single sub-module with ~7 kg of isotope ~20 sub-modules for 100+ kg of isotope surrounded by shielding 5 m 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 28
SuperNEMO design study February 2006 – January 2009 • Approved in UK, France and Spain. Similar proposals under consideration in Russia, Czech Republic, Japan • Main tasks and deliverables • R&D on critical components • Calorimeter energy resolution of 4% at 3 MeV • Optimisation of tracking detector and construction (robot) • Better background rejection (e.g. extra veto counters) • Ultrapure source production and purity control • Simulations and geometry optimisation • Technical Design report • Experimental site selection (Frejus, Canfranc, Gran Sasso, Boulby) 5 m 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 29
R&D: SuperNEMO calorimeter • Goal: FWHM 7%/E 4% at 3 MeV (Currently 14-16%/E in NEMO3) • A combination of energy losses in the foil and calorimeter DE/E • Studies • Organic (plastic or liquid), • Shape, size, coating • PMTs (Photonis, Hamamatsu, ETL) • Light guides, optical contact • Chemistry High QE Hamamatsu tube = DE/E = 6.5% at 1 MeV 3.8% at 3 MeV if 1/E + BC404 scintillator wraped in teflon See Jean-Stephane's talk for details 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 30
R&D: tracker optimisation • optimize: • wire length and diameter • wire material and diameter, • read-out, gas mixture etc • 9-cell prototype built • 90 cell prototype + 300 cell prototype to be built by Spring 2008 • About 500k wires to be strung, crimped, terminated => wire robot under development 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 31
e- prompt e- Bi-Po Process 238U 214Po (164 ms) b 214Bi (19.9 mn) a 210Pb 22.3 y Scintillator + PMT 0.021% 210Tl (1.3 mn) Tracking (wire chamber) 232Th Source foil (40 mg/cm2) 212Po (300 ns) b 212Bi (60.5 mn) Shield radon, neutron,g a 208Pb (stable) 36% e- a delay 208Tl (3.1 mn) R&D : radio purity and BiPo device • Need to measure radio purity at a few mBq/kg level • Beyond sensitivity of conventional Ge detectors • Build new tool, BiPo detector. a Delay a 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 32
Qbb (MeV) Isotopic Abundance R&D: isotope enrichment/ purification Choice of nucleus depends on: • enrichment possibilities • high Q value larger phase space lower non- background • small 2 contribution • 4 kg of 82Se funded by ILIAS • have been delivered from Russia. • purification at ILN (US) underway • enrichment of Nd possible in France (MENPHIS, currently mothballed) Two main options: G0(150Nd) / G0(82Se) = 8 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 33
2010 2011 2007 2008 2009 2012 2013 NEMO3 Running TDR R&D SuperNEMO BiPo construction SuperNEMO 1st module construction construction of 20 modules RUNNING of Full detector SuperNEMO schedule summary BiPo1 Canfranc BiPo installation BiPo running @ Canfranc Preparation of the site 6 SuperNEMO modules running @ Canfranc Final SuperNEMO modules installation 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 34
Conclusion NEMO’s Tracking+Calorimetry approach is unique: -high background rejection - choice of isotopes - reconstruction of kinematics NEMO 3 is taking data: - factory, important for understanding of backgrounds and NME -limits on using different isotopes: -T1/2 (> 5.8 x 1023 y @ 90% CL for 100Mo <m> < 0.8-1.3 eV (693 days); l'111 < 1.5 x 10-4 -limits on Majoron's coupling -T 1/2() = (7.6 ± 1.5 (stat) ± 0.8(syst)) x 1020 y for 130Te SuperNEMO R&D approved in France, the UK and Spain; TDR expected in 2008; full 20 modules in 2012-2013 -choice of isotopes: 82Se or 150Nd 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 35
Backup slides 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 36