SuperNEMO Double Beta Decay Experiment. A.S. Barabash, ITEP, Moscow (on behalf of the SuperNEMO Collaboration)

Transcription

1 SuperNEMO Double Beta Decay Experiment A.S. Barabash, ITEP, Moscow (on behalf of the SuperNEMO Collaboration) 1

2 OUTLINE NEMO-3 SuperNEMO DEMONSTRATOR: present status and plans for the future 2

3 NEMO-3 Collaboration (Neutrino Ettore Majorana Observatory) 60 physicists, 17 labs 01/09/11 33

4 Sector interior view PMT cathode rings wire chamber calibration tube scintillators Calibration source Bi 2e (IC) lines ~0.5,~1 MeV 90 Sr 60 Co 207 ββ isotope foils 4

5 ββ events selection in NEMO-3 Typical ββ2ν event observed from 100Mo Transverseview view Transverse Run Number: 2040 Run Number: 2040 Event Number: 9732 Event Number: 9732 Date: Date: Vertex emission 100 Longitudinal view Longitudinal view 100 Mo foil Geiger plasma longitudinal Vertex propagation emission Mo foil Deposited energy: E1+E2= 2088 kev Internal hypothesis: ( t)mes ( t)theo = 0.22 ns Common vertex:scintillator ( vertex) = 2.1 mm + PMT ( vertex)// = 5.7 mm Trigger: at least 1 PMT > 150 kev 3 Geiger hits (2 neighbour layers + 1) Trigger rate = 7 Hz ββ events: 1 event every 2.5 minutes 5

6 NEMO-3 was stopped in January stable operation in the Modane Underground Laboratory 7 isotopes (48Ca, 82Se, 96Zr, 100Mo, 116Cd, 130Te and 150Nd) were investigated: - precise half life values (2ν) for ALL 7 isotopes were obtained (energy and angular distributions were measured) - strong limits on decays with Majoron emission were obtained for all isotopes - strong limits on 0ν decay of 100Mo, 82Se, 150Nd and 96Zr were established Data analysis is in progress. Final NEMO-3 results will be published in See Laurent Simard presentation 6

7 Why not to use this technique for new (SuperNEMO) experiment? 1) Main idea is: to use very well known NEMO technique: - full event reconstruction - clear event signature - excellent background rejection - new physics studies1) using event topology (mass mechanism, RHC, excited states, ) Other ideas: - to use planar geometry (instead cylindrical) - to use modular system - to select isotope with which maximal sensitivity can be reached - to improve some parameters of the detector (energy resolution, efficiency, ) Eur.Phys.J.C70 : ,2010 7

8 NEMO-3 SuperNEMO T 0ν 1/ (nσ ) = nσ n σ n u m b e r o f s td. d e v. fo r a g iv e n C.L. a is o to p ic a b u n d a n c e 100 Mo 7 kg A(208Tl) < 20 µbq/kg A(214Bi) < 300 µbq/kg Rn ~ 5-6 mbq/m3 18% 8% 3 MeV y εa M t W b E M to ta l m a s s o f th e s o u rc e (k g ) t tim e o f d a ta c o lle c tio n (y ) ε d e te c tio n e ffic ie n c y W m o le c u la r w e ig h t o f th e s o u rc e NEMO-3 26 b b a c k g ro u n d ra te in c o u n ts (k e V k g y ) E e n e rg y re s o lu tio n (k e V ) R&D since 2005 isotope mass Radio-purity of the foil Radon in the tracker efficiency Energy resolution T1/2(0νββ) > 1024 y <mν> < ev sensitivity 1 module modularity SuperNEMO 82 Se ( maybe also 150Nd or 48Ca) kg A(208Tl) < 2 µbq/kg A(214Bi) < 10 µbq/kg Rn < 0.1 mbq/m3 30% 4% 3 MeV T1/2(0νββ) > 1026 y <mν> < mev 8 >20 modules (new lab) 8

9 SuperNEMO Collaboration ~ 100 physicists, 11 countries, 25 laboratories USA MHC INL (U Texas) Spain U Valencia U Saragossa U Barcelona Japan U Saga KEK U Osaka Marocco Fes U UK UCL U Manchester U Warwick Imperial College France CEN Bordeaux CPPM LAL ORSAY LPC Caen Finland U Jyvaskyla Russia JINR Dubna ITEP Moscow Ukraine INR Kiev Slovakia (U. Bratislava) Czech Republic Charles U Praha IEAP Praha 9

10 Single sub-module with ~7 kg of isotope ~20 sub-modules for 100+ kg of isotope surrounded by shielding 10

11 SuperNEMO 20 modules A module Demonstrator module 20 Modules 7 kg 140 kg Electron calorimeter γ veto (up and down) y y Source : 82Se Drift chambers for tracking T1/2 sensitivity <mν> sensitivity (No background) mev mev Demonstrator module(7 kg) under construction 11

12 Possible location: new LSM 12

13 SuperNEMO demonstrator module 13

14 R&D program was realized during last few years Calorimeter Tracker Source Purity measurements 14

15 SuperNEMO : Calorimeter PMT XP 1886 FWHM = 7,1 % (7,6% before energy loss correction) Volume: 8 l (NEMO3 4 l) 8 PMT (NEMO3 5 PMT) E/E % Factor 2 less compared to NEMO3 BiPo-3 module 15

16 SuperNEMO : Tracker Wiring robot 90 cells prototype cells prototype : data with cosmic rays

17 82 Se source Enriched Se: - 5 kg exist ~ 2 kg will be produced in 2012 Purification of Se: - distillation - chemical purification Source production: - to use the same method as for NEMO-3 - new approaches m 17

18 SuperNEMO : BiPo detector To measure source foils at the level of: - 2 µbq/kg for 208Tl - 10 µbq/kg for 214Bi using the Bi Po delayed coincidence in U and Th chains BiPo 3 Installation of BiPo 3 in LS Canfranc BiPo-3 module Optical 18

19 SuperNEMO schedule highlights NEMO-3 decommissioning Demonstrator construction Demonstrator physics run start-up Full detector construction start-up Target sensitivity (~0.05 ev) KK claim to be verified with Demonstrator by

20 BACKUP SLIDES 20

21 BiPo-3 detector Total active area = 3.25 m2 Detector composed of 2 modules Each module is an array of 40 optical sub-modules A pair of optical sub-modules consists of 2 thin scintillators face-to-face coupled via PMMA optical guides to 5" low-radioactive PMT Total of 80 PMTs + Optical guide + scintillators Scintillators: Polystyren based, size: mm3 entrance active face aluminized with 200nm of ultra pure Aluminium BiPo-3 module Optical Module 21