19 March 2009 Thomas Mueller - Workshop AAP09 1
The Double Chooz reactor neutrino experiment
Thomas Mueller – CEA Saclay Irfu/SPhN
Thomas Mueller - Workshop AAP09 219 March 2009
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 319 March 2009
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
3
2
1
1212
1212
1313
1313
2323
2323
100
0
0
0
010
0
0
0
001
cs
sc
ces
esc
cs
sci
ie
Atmospheric ν Solar νCHOOZ experiment
Thomas Mueller - Workshop AAP09 419 March 2009
Current knowledge on neutrino mixing parameters
T. Schwetz et al.NewJ.Phys.10:113011,2008Experimental measurements
Hints for θ13 > 0G.L. Fogli et al.Phys.Rev.Lett.101:141801,2008
Best global limit on θ13
Global (90% CL)sin2θ13 < 0.035
sin2θ13 = 0.016 ± 0.010 (1σ)
Thomas Mueller - Workshop AAP09 519 March 2009
Reactor neutrino oscillations
E
Lm
E
LmP ee 4
sin2sincos4
sin2sin1)(2
21212
213
42
31213
2
Nucifer Chooz KamLAND
DC
ne
ar d
etec
tor
DC
far
det
ect
or
Thomas Mueller - Workshop AAP09 619 March 2009
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 @ Δm31
2=2.5 10-3 eV2 (90% CL)
e ?,, e
Thomas Mueller - Workshop AAP09 719 March 2009
The Double Chooz collaboration
Collaboration meeting @ Chooz (June 2008)
France: APC Paris, CEA/Irfu Saclay, Subatech Nantes, Strasbourg
Germany: Aachen, MPIK Heidelberg, TU München, EKU Tübingen, Hamburg
Spain: CIEMAT Madrid
UK: Univ. Sussex
Japan: HIT, Kobe, MUE, Niigata, TGU, TIT, TMU, Tohoku
Russia: RAS, RRC Kurchatov Institute
USA: Alabama, ANL, Chicago, Columbia, Drexel, Illinois, Kansas, LLNL, LSU, Notre Dame, Sandia, Tennesses, UCD
Brazil: CBPF, UNICAMP
Spokesman: Hervé de Kerret (APC)
Thomas Mueller - Workshop AAP09 819 March 2009
The Double Chooz experiment
2 PWR-N42 x 4.27 GW
~ 1021 ν/s
• Phase I(2010-2011)Far detector
only
• Phase II(2011…)
2 detectors near and far
2 « identical » detectors
Far detector (1050m) ν oscillation300 m.w.e.
Near detector (400m) Flux normalization
115 m.w.e.
Chooz B nuclear power plantArdennes, France
Thomas Mueller - Workshop AAP09 919 March 2009
Antineutrinos detection
Inverse β decay:
Clear signature of an antineutrino reaction in the detector → powerful background suppression
nepe
*GdGdnPrompt signal:photons from e+e-
annihilation
epnvis mmmEE )(
Delayed signal:photons from n capture on Gd
Δt ~ 30 µs, E ~ 8 MeV
Thomas Mueller - Workshop AAP09 1019 March 2009
Detector design
Acrylic target vessel10.3 m3 Gd-doped LS
Acrylic γ-catcher vessel22.6 m3 LS
Stainless steel Buffer110 m3 mineral oil ~ 400 PMT
Inner veto90 m3 LS ~ 80 PMT
Shielding15 cm steel
Outer vetoplastic scintillator panels
Calibration glove-box
(εdet ~ 80%)
Thomas Mueller - Workshop AAP09 1119 March 2009
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 1219 March 2009
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 1319 March 2009
Near lab preparation
Site engineering study complete Tender process for construction soon Schedule: lab is finished in 2010
Thomas Mueller - Workshop AAP09 1419 March 2009
Statistical & systematic errors
CHOOZ: R = 1.01 ± 2.8% (stat) ± 2.7% (syst)
CHOOZ Double Chooz
Target volume 5.55 m3 10.3 m3
Target composition 6.77 1028 H/m3 6.55 1028 H/m3
Data taking period few months 3-5 years
Event rate 2700 FD 40000/3y - ND 106/3y
Statistical error 2.8% 0.5%
Statistical error
Hth NPtL
Systematic error
Two identical detectors σsys=0.6%
Thomas Mueller - Workshop AAP09 1519 March 2009
Expected θ13 sensitivity
Phase I
Phase II
σsys=2.5%
σsys=0.6%
CHOOZ limit is reached in 1 month!
sin22θ13 < 0.06sin22θ13 < 0.03
Thomas Mueller - Workshop AAP09 1619 March 2009
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