Christchurch, New-Zealand
May 26th 2008

Neutrino 2008 Conference

CEA/Saclay & APC

Thierry LasserreTowards θ13:
Double Chooz andnon-asian efforts

T. Lasserre 26/05/2008

 sin2(2θ13) measurement independent of sign(∆m213)- a few MeV νe + short baselines  negligible matter effects (O[10-4] ) weak dependence in ∆m221- 1-P(ννe→ νe) = sin2(2θθ13)x(sin2(∆∆m231L/4E) + O(∆∆m221/∆∆m231))- <Eν> ~ a few MeV electron antineutrinos  only disappearance experiments
 sin2(2θ13) measurement independent of δ-CP

θ13 & reactor experiments- Improvement in the determination of the other mass parameters- Quantitative Measurement of Natural Neutrino Sources- Determination of a fundamental physics parameter- The step before the Search for CP violation in the electroweak sector−iδνe  1 0 0  c13 0 s13e  c12 s12 0ν1   
 1 0 − s12 c12 0ν2 νµ  = 0 c23 s23 0ν  0 − s c − s eiδ 0 c  0 0 1ν 2323  1313  τ  3 

Motivations for θ132Clean θ13
measurement

T. Lasserre 26/05/2008

300 mwe

M=5t

D = 1050 m

Pth= 8.4 GWth- anti-νe + p  e+ + n,- <E>~4 MeV, Ethr=1.8 MeV- Disappearance experiment: search for a departurefrom the 1/D2 behavior + shape distortion- Isotrope anti-νe flux from 235/238U & 239/241Pu- β- fission products – 800 nuclei, 10000 branches)-1021 νe/s for commercial reactor core
- Fuel evolution (burn up)(90% C.L)
3sin2(2θ13) < 0.15@∆∆m2atm = 2.5 10-3 eV2νe → ν xM. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374

Best current constraint: CHOOZ

Chooz Nuclear Power Station
2 cores of 4.27 GWth eachArdellier et. al, hep-ex/0405032

1021 νe/s

Near detector

νe

νe,µµ,ττ

Far detector
Near detector
1050 m
400 m
T. Lasserre 26/05/2008

νe,µ,τ

Far/Near ratiosin2(2θθ13)=0.12

4∆m2atm= 3.0 10-3 eV2e+ spectrum
Far Detetector
Stat. Errors

Lev Mikaelyan (Kurchatov, 2000)

The - new - conceptP(ννe→ νe) = 1-sin2(2θθ13)sin2(∆∆m231L/4E)
Far detector

2002-2004
2007

Diablo Canyon

Braidwood

Angra

PenlyChooz
Cruas
DoubleChooz

T. Lasserre 26/05/2008

TaiwanKashiwasaki

Reno

Daya bay

2nd generation: sin2(2θ13)  0.01

1st generation: sin2(2θ13)~0.02-0.03

Krasnoyarsk

5

2002-2006:
Looking
Projects
discussed
in formy sites
Talk

Neu
trin
o200
8Demarc
ation
L
ine2

Angra

Courtesy J. Anjos/D. Reyna

Angra II

Near Site

T. Lasserre 26/05/2008

Angra III (in construction)

Far Site

6-Realization of a Small Neutrino Detector for Non Proliferation (See N. Bowden’s Talk)-Angra collaboration merge with Double Chooz in 2006

θ1-Prospect for a sin (2θ13)<0.01 after Double Chooz
In 3 @- Angra II-III reactors (2 x 4.0 GW) ,ST A
AN NG- 1.5 km tunnel to escavate for the far det. + a shaft/tunnel for the near det.
D RA
- Large detector (a few hundreds tons) focusing on spectral measurement
BY

UFABC

http://doublechooz.in2p3.fr/

Thierry Lasserre
CEA/Saclay & APC
On behalf of theDouble Chooz Collaboration

U.S.A
RussiaU.K.

JapanBrazil

Spain
Germany

FranceDouble Chooz

ChoozArgonneT. Lasserre 26/05/2008

82008

06060252007

ep/ex2006

sal:h2004

2005

Propo2003

Double Chooz Collaboration

CharlevilleChooz

Knoxville
Kobe

--

2,7%

Statistical error

T. Lasserre 26/05/2008

Two Detector Concept
Improved detector design:
Lower threshold, e+ and n Efficiencies,Calibration System
Lower Background: Shielding, Radiopurity– Systematic & Background errors –

2700

0,5%

Far: 40000 / Near: 500000 (3 y)10,3 m3
6,55 1028 H/m3
3-5 years

5,55 m3
6,77 1028 H/m3Few months

Double Chooz

CHOOZ

9Luminosity incerase: L = ∆t x P(GW) x NTarget H

Event rate

Target volume
Target composition
Data taking period– Statistical error –Best Sensitivity @CHOOZ: R = 1.01 ± 2.8%(stat)±±2.7%(syst)

Improving CHOOZ: key facts

T. Lasserre 26/05/2008

10

The site in French Ardennes

Far

Near

300 mwe
Hill topology

998 m

115 mweFlat topology
T. Lasserre 26/05/2008

1115 mIso - Near/Far flux

351 m
465 m

West Reactor

11East Reactor

The site in French Ardennes

- µ-Rate: ~20 Hz @IV- Fire system being upgraded- Pit refubrished- Neutrino laboratory:-1- 1 km baseline (15000 y )- 300 m.w.e. (hill topology)

NeutrinoLaboratory(14°C)

12Safety files ready (being processed by French authorities)
T. Lasserre 26/05/2008-Liquid storage building- Being upgraded- First liquids in the summer (Veto/Buffer)-Tunnel : 200 meters @10%
- Ready!
- New ventilation system, doors, safety, …

Chooz-A Power Plant
Being dismantled

Tunnel entrance
Tunnel: 200 m

Liquid Storage Building

Far Site Status

T. Lasserre 26/05/2008- Site Engineering Study
CompletedHillside- Tender process for construction soon
- Schedule: laboratory delivery end of 2009-- A tunnel to access the lab(but no shaft)-- Motivations: Escavation, Safety, Detector
integration, Cost, Schedule (no physics loss)

Schiste-Gres rock

Neutrino Lab- Laboratory site
- labo at ~400 m from nuclear cores (150 000 y-1)
- 115 m.w.e (almost flat topology)- µ-Rate: ~250 Hz @IV

DC Higgs building …

100 m

85 m open air ramp
155 m of gallery

13Near Site Status

Reactor level(NGF 120 m)

36 m

Near Detector level (NGF 82 m)
Far Detector level (NGF 84 m)

85 m open air ramp (14%)

Liquid Handlingand Storage

85 m open air ramp(14%)

T. Lasserre 26/05/2008

155 m of gallery (12%)>45 m rockoverburden

Hill side (+20m)

155 m of gallery(12%)

Neutrino Lab

12 m

54.

38 m

14

Near Site Drawings
24 mm

n
Σγ ~ 8 MeV

Gd

Far:
Near+
Σγ ~ 8 MeV

Gd

2 neutrinos d-1
11 neutrinos d-1

Eγ >~ 1 MeV

γnAccidental Backgroundνe511 keV+
p e511 keVe- antineutrino Signature

T. Lasserre 26/05/2008

70 neutrinos d-1
500 neutrinos d-1

1.6 neutrinos d-1
5.2 neutrinos d-1

Σγ ~ 8 MeV

GdNeutron slowing/thermalisation

15

Space correlation: <1 m

Correlated Background

Far:
Nearn

Far:
Near

Time correlation: τ∼30 µs

Prompt e+ (1-8 MeV) Delayed n Gd-capture (8 MeV)

Background & Design

CEA-DSM-IRFU (thechnical coordination)

Electronics& DAQ

T. Lasserre 26/05/2008
16(4 liquid densities adjusted at 0,800≤0,005)

Veto Vessel (10mm) & Steel Shielding (150 mm)

vessel equipped with 78 PMTs

Inner Veto: 90m3 of scintillator in a steel

steel vessel (3 mm) viewed by 390 PMTs

Buffer: 110 m3 of mineral oil in a stainlessvessel (12 mm)

γ-Catcher: 22,3 m3 scintillator in an acrylicof Gd compound in an acryclic vessel (8 mm)

ν-Target: 10,3 m3 scintillator doped with 0,1g/l

Outer Veto: plastic scintillator strips (400 mm)

http://bama.ua.edu/~busenitz/rnu2003_talks/lasserre1.doc

New 4-region large detector conceptfrom Double Chooz Coll. (2003)

Detector
DesignJuly 2005

ReceptionReceptionAoût 2005

Integration
Integration

May 2005

Conception
Conception

OperatingOperating66 months
monthsT. Lasserre 26/05/2008

December 2005

Filling
Filling
September 2006

Dismantled
Dismantled

17

Leak Test

Cleaned
CleanedValidation of the technical choices for the vessels (120 l Gd-doped LS):
construction, material compatibility, filling, and the integration

Technical 1/5 mockup in 2005

80 x 8 m long bars

8m18

Bar demagnetization ongoing at Chooz
T. Lasserre 26/05/2008- 1 cm thick steel vessel for tightness- γ’s from rock (2 ppm U, 5 ppm Th, 14000 ppm K)- 15 cm steel shielding low radioactive(250 tons of steel delivered, 10-9 g/g U/Th)- Construction & integration Ongoing

γ ray shiedling & Veto vessel

VesselManufacturingongoing

R&D & design
completed½ stainless steel
delivered:- 10-9 g/g U/Th &- 15 mBq/kg Co

Buffer : 3 mm

Tender ongoing

R&D & Design
completed customised
acrylic batch

Target : 8 mm
γ catcher : 12 mm

StatusScale 1chimney

TargetVesselConstruction

T. Lasserre 26/05/2008

VM stress: 23 MPa

VM stress: 1 MPa

Design(stress/disto.)γ-catcher

19Transport & Integration
Critical for the acrylics vessel

Mechanics: Acrylics and Buffer

Theoretical understanding of theenergy transfers (Confirmed bymeasurements)

Features:- Solubility (5 g/l)
- Attenuation length (full mixture)>10m@430 nm- Good stability (rigid complex)
Stability: tested for 3 y @20oC- LY ~60%BC505- Good for material compatibility(Ph neutral)- Good Radiopurity (sublimation)- 226Ra+235U+228Ra+228Th+152Eu< 150 mBq/detector- 40K < 500 mBq/detector

New DC Development:- Solvent: 20% PXE (C16H18) + 80%
Dodecane (C12H24) + PPO/Bis-MSB- 1 g/l Gd(dpm)3: tris-(2,6-tetramethyl3,5-heptanedione) Gd(III)T. Lasserre 26/05/2008

20

A New Type of Gd-scintillator

Delivered

3 iso-tanks ready fortransportation, storage & filling
T. Lasserre 26/05/2008

MPIK new building for LS
storage, mixing and purification- Buffer Oil Ordered- PVDF coated Target Transport Tank (6m3)- Target Solvant: 20% PXE – 80% Dodecane- GC Solvant: 4 % PXE – 46% Dod. - 50% Oil- 100 Kg Gd compound delivered- A SINGLE Batch LS for both detectors

21

Inner Det. Liquid ProductionDFOS &Auxilary,
Safety Systems

EnGC 25 Neutrino
m3
Laboratory
Isocontainer

tran14m

T. Lasserre 26/05/2008

ce Far Detector
1Fluid BuildingEn
trance29m

Target 4x6m3
Tanks
Tunnel PVDF
Entrance

Weight sensor + Flux meter system for Target H measurement @0,2%

22

Stainless Steel
Veto Tank
3x30 m3

Stainless Steel
Buffer Tank
3x40 m3- Target Weighing Tank underground for: Filling, Target H meas., and recirculation

Height tolerance between the 4 volume is a 3 cm ∫max  complex level control system- DFOS handles the filling, recirculation, glove box operation for all four liquids

Detector Fluid Operating SystemMu-metal Magnetic shielding delivered
PMT supporting structure in production
Customized PMT based + FEE designed

Full PMT caracterisation & Testing ongoing







T. Lasserre 26/05/200810‘‘ Hamamatsu tubes + 1 HV channel/PMT- 390 PMTs  ~15 % coverage- Energy Resolution goal: 7 % at 1 MeV- New Low Background Glass Production
 PMT radiopurity Singles < 5 Bq/det- PMT Ordered & Delivery in progress

23

Inner detector (ID) Photodetection

IMB PMT (R1408) +encapsulation

T. Lasserre 26/05/2008- 50 cm, scintillating LAB oil (ordered)~78 IMB PMTs (8“) delivered- Reflective walls (ext. paint + int. Tyvek)

Inner Veto : tag efficiently cosmic raymuons & external fast neutrons
entering the detector

24

Inner Veto (IV)Storage- DAQ being prepared (deadtimeless)- F-ADC CAEN V1721 (500MHz & 8-bits)- F-ADC/TDC for showering µ (500MHz & 10-bits)- L1 Trigger board readybeingordered• Amplification x15 – Pulse shape – Baseline correction• Dedicated Showering Muon electronics (9Li-8He bkg)
• Analog Pulse Summation for Level 1 Trigger• Single cable for HV + PMT signal- HV+Front-End:

390 (Target) +78 (Veto) PMTs

(ν-like ≠ µ-tagged)

Event builder(2 coincident Level 1 triggers)

Level 2 trigger (software)(analog sum above ~0.4MeV)

Level 1 trigger (harware)
FIFO

ID+IV electronics & DAQ

4 x 6.4 m2+ umbrella

Mirrored fiber ends

T. Lasserre 26/05/2008

2 x 6.4x6.4 m2

Status: Prototype underconstruction. Material procurement
for both detector started

Near detector:Far detector:

Technology: Panels of strips ofcoextruded plastic scintillator +TiO2
reflector with 1.2 mm diameter
wavelength shifting fiber

Tag “near miss” µ. Redundancy
for higher rejection power- IV calibration- Fast Neutrons rejection

Scintillator strips

Al skin for module

Fiber routing

FE cardFiber holder

26

M64

Outer Veto system

Embedded LED
calibration system
385, 420, 470 nm

ArticulatedArm

Fish-line

T. Lasserre 26/05/2008

Buffer guideTube
27

GC guide Tube

Glove BoxDetector Calibration Systems

T. Lasserre 26/05/2008

All materials in contact with liquid being
exposed to liquids for validation with highexposure (time x surface)- Material compatibility:- Particle counting & deposition rate
- Radon measurement- Dust radiopurity measurements

28

Extensive use of underground germanium
counters for material qualification:- Heidelberg/Munich- Gran Sasso (Thanks!)- Modane (Thanks!)- Oroville (Thanks!)- Dedicated counter in Saclay

The Chooz lab. is being transformed– step-by-step- to an ISO 5 clean room
during detector integration- Far lab characterization on-going- Radiopurity- Cleaningness

Cleaningness & RadiopurityAttenuation Length

T. Lasserre 26/05/2008- Read-out System simulation(Electronics & DAQ)
- Neutrinos + background generators
 A Lot Of Input Lab. Measurements ...

(quantum & collection efficency)- PMT geometry and optics(emission, reemission, energy transfers …)

Proofed Geant4-based (KamLAND) +- Scintillation and Microscopic Optical Model

Detector Uniformity

Targetγ-Catcher

29

Scintillator Fluorescence Time

Detector Simulation

Full simulation – Geant + Fluka
Old Chooz simulation  MC is reliable- Simulated: 0.8 d-1- Measured in-situ: 1 d-1
Double Chooz simulation:- Far detector: 0.2 d-1- Near detector: 0.7 d-1

T. Lasserre 26/05/2008- Long-lived Spallation Products 8He 9Li 11Li
β decay followed by n emission (τ~100 ms)- CHOOZ Reactor-OFF -non official- Analysis- Far: 1.4 d-1- Near: 4.5 d-1β-neutron cascades--Fast Neutrons- Estimations based on n flux measured at Chooz- Singles dominated by PMTs
- Single Rate <10 Bq @ >0.7 MeV

Accidental BackgroundGdn from µcaptureµ capture

050D51015de+n‹ 100 cm

dn › 30 cm

de+ › 30 cm+30 30µe -like Energy (MeV)252 ‹ ∆t ‹ 100 µs

20C10Bν candidate region

AReactor OFF

1520

2530µ interaction
on 12CSpallation
fastneutronGdn capture Recoil p
on Gd

Recoil pµ

Backgrounds Studies

n-like Energy (MeV)Conversion method(Schreckenbach)Ratio Beg/End Fuel Cycleν spectrum from nuclear databases
Inputs: nuclear databases, theory of βdecay + models (104 β-branches)

T. Lasserre 26/05/2008

31Error Bars Reduced x2-3 for Eν< 5 MeV + Full Error Propagation and Correlations included Improvement of Shape analysis possibilities for Double Chooz Phase I (Far detector only)

Chooz 2 x N4
205 fuel assembliesbNo free parameter

fpTime evolution of nuclear fuelInputs: initial fuel and Pth(t)νS tot( E ) = ∑ N fp × ∑ BR fp b S νfp b ( Z fp , E 0fp b , E )A New Reactor-νν ModelPowerRel. Norm.
Spectrum
Background rates

Best
1.0%
0.4%
1.0%
X0Central
2.0%
0.6%
2.0%
X1- Robustess (pulls method)

90% C.L. limit if no-oscillation:sin2(2θ13)<0.032- Nominal sensitivity- 3 years of data (50 000 evt/far)- ∆m231 = 2.5 10-3 eV2- Assumptions

Analysis

Detector induced

Reactor-induced

T. Lasserre 26/05/2008

Worst
3.0%
0.8%
3.0%
X2

- 2 detectors simulateously- Account for neutrino spectrum- Known backgrounds & systematics
and their uncertainties- Chi2 Analysis

Total

1.0 %

Spatial effects

From 7 to 3 cuts

2.7 %

1.5 %

-1.2 %

H/C ratio & [Gd]Live time

0.3 %

0.3 %

Target MassDensity

0.3 %0.7-2 %

1.9 %Solid angle

Reactor powerν flux and spectrum

Chooz

32

< 0.6 %

0.2 - 0.3 %<0.2 %<0.1 %<0.2%<0.1 %

0.2 %<0.1 %<0.1 %<0.1 %

Double Chooz

Sensitivity & Robustness
G. Mention et al, hep-ex, arXiv:0704.0498, submitted to Phys. Rev. D)

G. Mention, T.L., D. Motta

0123years

T. Lasserre 26/05/2008

45

Excluded by CHOOZ

σsys=0.6%

Far detector Both detectors(1km) alone 1 km & 400 m

σsys=2.5%∆m2atm = 2.5 10-3 eV2 (20% uncertainty)

ComplementaryWith T2K• Systematics 2Det:- σabs = 2.0%
- σrel = 0.6%
- σscl = 0.5%
- σshp = 2.0%
- σ∆m2= 20%33• Systematics 1Det = CHOOZ• 1% ‘bin-bin’ uncorrelated error
on background subtraction.

• Efficiencies included

Sensitivity (Limit) Timeline

2008-102011

sin2(2θ13) < 0.03 after 3 years (90% C.L.) if no-oscillation

 Near Lab Escavation & Near Detector Integration
 Start of phase II : Both near and far detectors

sin2(2θ13) < 0.06 after 1,5 year (90% C.L.) if no-oscillation

2008-09  Far Detector construction & integration
Middle 09  Start of phase I : Far 1 km detector alone Faisability study on non proliferation with Double
Chooz near detector ongoing (See N. Bowden’s Talk)-- First goal: measurement of θ13

 Double Chooz Far integration Started in May 08

Conclusions & outlook

Detector Pit May 22th 2008

May 2008: Integration Starts

T. Lasserre 26/05/2008

1y35

Middle 2009: 1st ν-Event To be Recorded?

Outlook …

T. Lasserre 26/05/200836

Collaborating Institutions

T. Lasserre 26/05/2008

37

Detector BreakdownAnalysis

few %
1.5 %

Live time

From 7 to 3 cuts

< 0.6 %

0.2 - 0.3 %<0.2 %<0.1 %

T. Lasserre 26/05/2008

2.7 %

1.0 %

Spatial effects

Total

0.2 %

<0.2%

0.3 %

Target Mass

<0.1 %

1.2 %

0.3 %

Solid angle<0.1 %<0.1 %

0.6 %Energy perfission<0.1 %<0.1 %

0.3 %

0.7 %

1.9 %

Reactor power

Detector Density- induced
H/C ratio &Gd concentration

Reactorinduced

ν flux and σChooz38(Total ~0.45% without contigency)

Few Cuts

Measured with several methods‘’identical’’ Target geometry & LS

Same scintillator batch + Stability

Near/Far T control

Relative Mass Measurement

Distance measured @10 cm

Two ‘’identical’’ detectors,
Low backgroundDouble Chooz (relative)

Systematic Error Budget