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