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The Double Chooz reactor neutrino experiment. Thomas Mueller – CEA Saclay Irfu/SPhN. Overview. Neutrino oscillation Theory & status Neutrino oscillation @ reactor The Double Chooz experiment From Chooz to Double Chooz Neutrino detection and detector design Present status of the experiment
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The Double Chooz reactor neutrino experiment Thomas Mueller – CEA Saclay Irfu/SPhN Thomas Mueller - Workshop AAP09
Overview • Neutrino oscillation • Theory & status • Neutrino oscillation @ reactor • The Double Chooz experiment • From Chooz to Double Chooz • Neutrino detection and detector design • Present status of the experiment • Errors & expected sensitivity • Summary & conclusion Thomas Mueller - Workshop AAP09
Neutrino oscillations • Super-Kamiokande (1998) → first evidence of neutrino oscillation, non-zero mass • Oscillations are described by a mixing of flavour and mass eigenstates through unitary PMNS matrix • 6 parameters: 3 mixing angles, 2 mass differences & 1 complex phase CHOOZ experiment Solar ν Atmospheric ν Thomas Mueller - Workshop AAP09
Current knowledge on neutrino mixing parameters T. Schwetz et al. NewJ.Phys.10:113011,2008 Experimental measurements Best global limit on θ13 Global (90% CL) sin2θ13 < 0.035 G.L. Fogli et al. Phys.Rev.Lett.101:141801,2008 Hints for θ13 > 0 sin2θ13 = 0.016 ± 0.010 (1σ) Thomas Mueller - Workshop AAP09
Reactor neutrino oscillations DC near detector DC far detector KamLAND Nucifer Chooz Thomas Mueller - Workshop AAP09
From Chooz (1997-1998) to Double Chooz • Neutrino disappearance experiment 5 m3 of Gd-doped liquid scintillator L = 1.05 km • Highest systematic uncertainty → antineutrino flux emitted by reactor • Double Chooz: from absolute to relative measurement R = 1.01 ± 2.8% (stat) ± 2.7% (syst) sin22θ13 < 0.15 @ Δm312=2.5 10-3 eV2 (90% CL) Thomas Mueller - Workshop AAP09
The Double Chooz collaboration Spokesman: Hervé de Kerret (APC) France: APC Paris, CEA/Irfu Saclay, Subatech Nantes, Strasbourg Japan: HIT, Kobe, MUE, Niigata, TGU, TIT, TMU, Tohoku Germany: Aachen, MPIK Heidelberg, TU München, EKU Tübingen, Hamburg Russia: RAS, RRC Kurchatov Institute USA: Alabama, ANL, Chicago, Columbia, Drexel, Illinois, Kansas, LLNL, LSU, Notre Dame, Sandia, Tennesses, UCD Spain: CIEMAT Madrid Brazil: CBPF, UNICAMP UK: Univ. Sussex Collaboration meeting @ Chooz (June 2008) Thomas Mueller - Workshop AAP09
The Double Chooz experiment 2 « identical » detectors Far detector (1050m) ν oscillation 300 m.w.e. Near detector (400m) Flux normalization 115 m.w.e. • Phase I • (2010-2011) • Far detector only • Phase II • (2011…) • 2 detectors near and far 2 PWR-N4 2 x 4.27 GW ~ 1021ν/s Chooz B nuclear power plant Ardennes, France Thomas Mueller - Workshop AAP09
Antineutrinos detection • Inverse β decay: • Clear signature of an antineutrino reaction in the detector → powerful background suppression Prompt signal: photons from e+e- annihilation Delayed signal: photons from n capture on Gd Δt ~ 30 µs, E ~ 8 MeV Thomas Mueller - Workshop AAP09
(εdet ~ 80%) Calibration glove-box Outer veto plastic scintillator panels Acrylic target vessel 10.3 m3 Gd-doped LS Inner veto 90 m3 LS ~ 80 PMT Acrylic γ-catcher vessel 22.6 m3 LS Shielding 15 cm steel Stainless steel Buffer 110 m3 mineral oil ~ 400 PMT Detector design Thomas Mueller - Workshop AAP09
Far lab integration (1/2) June 08: Start of the work Sept 08: Shielding installation Nov 08: IV integration Dec 08 - Jan 09: Lab cleaning Thomas Mueller - Workshop AAP09
Far lab integration (2/2) Feb 09: IV cleaning… … ISO6 class tent mounting… … and IV PMTs installation Presently: Buffer installation First neutrino planned for end 2009 Thomas Mueller - Workshop AAP09
Near lab preparation • Site engineering study complete • Tender process for construction soon • Schedule: lab is finished in 2010 Thomas Mueller - Workshop AAP09
Statistical & systematic errors CHOOZ: R = 1.01 ± 2.8% (stat) ± 2.7% (syst) Statistical error Systematic error Two identical detectors σsys=0.6% Thomas Mueller - Workshop AAP09
Phase I Phase II σsys=2.5% σsys=0.6% Expected θ13 sensitivity CHOOZ limit is reached in 1 month! sin22θ13 < 0.03 sin22θ13 < 0.06 Thomas Mueller - Workshop AAP09
Summary and conclusions • First new generation neutrino experiment using two identical detectors at different distances to measure θ13 • Far detector installation in progress → first neutrino end 2009 • Far detector only: sin22θ13 < 0.06 in 1.5 years (90% CL) if no oscillation • Far and near detectors: sin22θ13 < 0.03 in 3 years (90% CL) if no oscillation Thomas Mueller - Workshop AAP09