Anti-neutrinos from nuclear reactors Chasing θ 13

Transcription

1 Anti-neutrinos from nuclear reactors Chasing θ 13 Double Chooz ICEPP, 18th of December 2006 H. de Kerret APC / Collège de France

2 Recent discoveries in Neutrino Physics

3 Neutrino oscillations

4 Neutrino mass matrix = ν ν ν ν ν ν δ δ τ μ c s s c c e s e s c c s s c i i e θ sol θ 13, δ θ atm

5 Constraining the neutrino sector [Δm θ 12 ] [Δm θ 23 ] sign(δm 2 32) - θ 13 - δ solar ν + KamLAND + reactor ν? atmospheric ν + K2K + MINOS Superbeams superbeam ν + reactor ν MSW-LMA Δm 2 12 ~O(10-4/-5 ) ev 2 sin 2 (2θ 12 )~0.8 (large angle) Δm 2 32 ~ ev 2 sin 2 (2θ 23 )~1 (maximal angle) sin 2 (2θ 13 )<0.20 (CHOOZ) θ 13? (small angle) Hierarchy sign(δm 2 32 )? CP violation δ phase? But no absolute mass scale coming from oscillation experiments --> β & ββ0ν decays?

6 θ 13 & beam experiments LBL ν μ disappearance : sin 2 (2θ 23 ) 2 solutions : θ 23 & π/2-θ 23 Δm solutions m 1 >m 3 or m 3 >m 1 Appearance probability : P(ν μ ν e ) ~ K 1 sin 2 (θ 23 ) sin 2 (2θ 13 ) + K 2 sin(2θ 23 ) sin(θ 13 ) sign(δm 2 31 ) cos(δ) K 3 sin(2θ 23 ) sin(θ 13 ) sin (δ) +... K 1,K 2,K 3 : constants known with experimental errors dependence in sin(2θ 23 ), sin(θ 23 ) 2 solutions dependence in sign(δm 2 31 ) 2 solutions δ-cp phase [0,2π] interval of solutions θ 13 sin 2 (2 θ 13 ) & reactor experiments reactor P(ν μ ν e ) ν beam <E ν > ~ a few MeV only disappearance experiments sin 2 (2θ 13 ) measurement independent of δ-cp 1-P(ν e ν e ) = sin 2 (2θ 13 )sin 2 (Δm 2 31 L/4E) + O(Δm2 21 /Δm2 31 ) weak dependence in Δm 2 21 a few MeV ν e + short baselines negligible matter effects (O[10-4 ] ) sin 2 (2θ 13 ) measurement independent of sign(δm 2 13 )

7 Complementarity with T2K Assumptions: Double Chooz starts 2009 (2 detectors) T2K starting with full intensity sin 2 (2Θ 13 ) = 0.08, Δm 2 23 = ev 2 (+1 year) 1.64σ (90 %) 3σ (99.73 %)

8 θ 13 seems in reach A Theoretician joke? Prediction 27 models predications 17 above between 0.01 and 0.03 Double Chooz 3y sensitivity

9 Neutrino oscillation from a reactor: as it was detected Double Chooz KAMLAND

10 50 Years of detector developments Huge progress: from 10 meters of the reactor core till 170 km (4 orders of magnitude; 8 orders on signal) Signal/Background ~ in recent experiment Backgrounds are well understood Slower progress Loaded scintillator: stability issue Reconstruction event position neutrino direction

11 Best current constraint: CHOOZ R = 1.01 ± 2.8%(stat)±2.7%(syst) ν e ν e (disappearance experiment) P th = 8.4 GW th, L = km, M = 5 t overburden: 300 mwe World best 2 atm = ev 2 ν e ν x sin 2 (2θ 13 ) < 0.12 (90% C.L) M. Apollonio et. al., Eur.Phys.J. C27 (2003)

12 : Publications EU Letter of Intent hep-ex/ White book - Main physicist streams bugey:declais,boucshez,dekerret shoenert oberauer hagner Proposal hep-ex/ Kamland:suzuki,suekane Savannah:soebel,svoboda Russia: skorokhvatov US Letter of Intent hep-ex/

13 ν e The events proton-rich liquid scintillator is both a target and detector p β + n Add Gd to reduce neutron capture time, increase capture energy ~30μs Eν = Ee Mev prompt delayed time β + signal: n capture: E ν - 0.8MeV ~ 8MeV

14 90% C.L. sensitivity if sin 2 (2θ 13 2 = ev 2 T2K 1% 0.1% reactor 1 (2 RNU) X 20 σ bkg σ bkg σ bkg reactor 2 (40 RNU) G. Men tion & T. L. Huber, Lindner, Schwetz & Winter: hep-ph/ RNU = Reactor Neutrino Unit : 1 RNU = free H GW th year Reactor 1 (0.5 km, 2.3 km): ~13 tons PXE x 10 GW x 3 years sin 2 (2θ 13 )<~0.02, 90% C.L Reactor 2 (0.5 km, 2.3 km): ~270 tons PXE x 10 GW x 3 years sin 2 (2θ 13 )<~0.01, 90% C.L

15 China/US collaboration Four reactor cores P=4 x 2.9 = 1.6 GW th + two new cores for 6 GW th in 2011 Civil construction Near: 1 km tunnel + laboratory Far: 2 km tunnel + laboratory ~10 tons detector modules Near: 25 tons m 200 mwe Far: 50 tons km mwe Movable detector concep Sensitivity 0.4% systematic error sin 2 (2θ 13 ) < ~ 0.01 (90% C.L.)? Prospects (not yet approved) : R&D, : Construction 1 Near detector running in 2008 Geological & safety studies ongoing Daya Bay

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17 Japan Tohoku Univ. Tokyo Metropolitan Univ. Niigata Univ. Tokyo Institute of Technology Kobe Univ. Tohoku Gakuin Univ. Miyagi University of Education Hiroshima Institute of Technol ogy USA Livermore nat lab Argonne Columbia Univ Chicago Univ Kansas U Notre Dame U Tennesse U Alabama U Drexel U collaboration France Saclay APC (formerly collège de France) Subatech nantes Germany Max planck Heidelberg Munich U Hamburg U Tubingen U Aachen U Spain CIEMAT Madrid England Oxford Sussex Russia Kurchatov inst Sc. Acad.

18 At Chooz, June 06 France, Germany,Spain funded. England, US and Japan expected before Summer 07 Already started building

19 + = Det. Bins k 2 k k 2 k k 2 σ α Error Uncor. Biases α Theory Data χ = = = = + = N,F A N 1 i K 1 k 2 A k A i,k 2 A i K 1 k A i,k A i,k A i A i 2 bins σ α U S α T O χ Efficiencies included 1% of background in Near & Far detectors Syst. uncert.: σ abs = 2.0% σ rel = 0.6% σ scl = 0.5% σ shp = 2.0% σ Δm2 = 20% Potential limit if sin 2 (2θ 13 )=0 Δm 2 = ev 2 3 years (efficiencies included) sin 2 (2θ 13 )<0.024

20 Near detector location Uncorrelated fluctuations included Relative Error : 0.6% Spectral shape uncertainty 2% Δm 2 known at 20% Power flucutation of each core: 3% Available and suitable area On the median ~250 m ~10% 3 years data taking Spent fuel effect under study kopeikin and al.

21 The site Chooz-Near Chooz-Far Near site: D~ m, overburden mwe Far site: D~1.1 km, overburden 300 mwe

22 Observable: e + spectrum Δm 2 atm = ev2 Events/200 KeV/3 years sin 2 (2θ 13 )=0.04 sin 2 (2θ 13 )=0.1 sin 2 (2θ 13 )=0.2 sin 2 (2θ 13 )=0.04 sin 2 (2θ 13 )=0.1 sin 2 (2θ 13 )=0.2 E (MeV) Near Detector: ~ events/3y -Reactor efficiency: 80% -Detector efficiency: 80% -Dead time: 50% E (MeV) Far Detector: ~ events/3y -Reactor efficiency: 80% -Detector efficiency: 80%

23 Expected signal Rate + shape information if θ 13 not too small Far/Near energy bin km Note: optimum baseline between ~1.2km and 1.8 km

24 Spectrum deformation information 1σ statistical errors only rate info: no-osc 2.66σ shape info: flat shape 5.98σ

25 The Double-Chooz concept ν e ν e,μ,τ 8.4 GW th Chooz PWR power station D 1 = m Near detector D 2 = 1,050 m Far detector anti-ν e flux (uranium 235, 238 & plutonium 239, 241) Reaction: ν e + p e + + n, <E>~ 4 MeV, E threshold =1.8 MeV Disappearance experiment: search for a departure from the 1/D 2 behavior and shape distortion improve Chooz sensitivity 0.03 Improve the detector concept and backgrounds rejection

26 : Detector design Bruit de fond accidentel n γ Eγ >~ 1 MeV + Gd Signal antineutrino électronique Σγ ~ 8 MeV ν e 511 kev Bruit de fond corrélé -Prompt e+, E prompt e + P =1-8 MeV, & capture n sur Gd p n e kev Gd Σγ ~ 8 MeV Time thermalisation correlation: neutron τ 30μsec - Delayed n captured on Gd nucleus, ESpace R =8 MeV correlation: < 1m Cible γ Catcher ν : 80% : 80% dodécane dodecane n Shielding: Zone Veto muons tampon % : non cm huile + PXE 20% steel scintillante +0,1% PXE (1 km Gd : detector) + huile 70 tubes minérale + photomultiplicateurs 70 PPO cm + & + PPO 534 sand Bis-MSB + photomultiplicateurs (280 Bis-MSB m detector) Gd Σγ ~ 8 MeV

27 New detector design 7 m ν target: 80% dodecane + 20% PXE + 0.1% Gd (acrylic, r = 1,2 m, h = 2,8 m, 12,7 m 3 ) 7 m ν e 511 kev p n 511 kev e + Gd Σγ ~ 8 MeV γ-catcher: 80% dodecane + 20% PXE (acrylic, r+0,6m V = 28,1 m 3 ) Non-scintillating buffer: same liquid (+ quencher?) (r+0.95m,, V = 100 m 3 ) PMTs supporting structure Muon VETO: scintillating oil (r+0.6 m V = 110 m 3 ) Shielding: 0,15 m steel

28 The Double-Chooz sites Chooz-far Chooz-near

29 Improving CHOOZ Statistical error R = 1.01 ± 2.8%(stat)±2.7%(syst) Luminosity increase L = Δt x P(GW) x V target Target volume Target composition Data taking period Event rate Statistical error CHOOZ 5,55 m 3 6, H/m 3 Few months ,7% Double-Chooz 12,67 m 3 6, H/m years CHOOZ-far : /3 y CHOOZ-near: > /3 y 0,4%

30 Improving CHOOZ Systematical error : σ sys =2.7% Decreasing systematical error 1. Improve the detector concept 2. Two identical detectors towards σ relative ~0,6% 3. Backgrounds improve S/B>100 error<1%

31 Relative Normalization: 1.5% syst. err. - 7 analysis cuts - Efficiency ~70% Goal Double-Chooz: ~0.3% syst. err. - 2 to 3 analysis cuts Selection cuts - neutron energy (- distance e+ - n ) [level of accidentals] - Δt (e+ - n) ν e pe + Gd n e + n Δt

32 Systematics Pull Х 2 analysis

33 Far site Near site Distance Reactordetector Required overburden (m.w.e) , m.w.e. overburden 12 m compacted earth 3 meter high density material DAPNIA 3,5m (under the crane) Ø4,2m 250 m 125 m DAPNIA Muon Veto Gamma Catcher Target Buffer

34 BACKGROUNDS

35 ν neutrino identification (signal) Eν = E e MeV 511 kev Backgrounds accidental background (uncorrelated) n ν e 511 kev p e + γ + Gd n Gd Eγ >~ 1 MeV Σγ ~ 8 MeV Σγ ~ 8 MeV prompt signal (e * 511 kev + n capture on Gd (H 2,Li,B, ) Distance e + -n ~ 6cm with some memory Of the neutrino direction n correlated background n deposits energy Gd Σγ ~ 8 MeV +β-n cascades

36 Neutron Induced Background μ μ Cosmic muons create fast neutrons through Spallation in the rock surrounding the detector muon capture in the detector materials Fast neutron slows down by scattering into the scintillator; it could deposit between 1-8 MeV and be later captured on Gd! Full simulation Geant + Fluka Old Chooz simulation: 300 m.w.e. 31hours MC is reliable! Simulated: N b <1.6 evts/day (90% C.L.) Measured in-situ: N b =1.1 evts/day Recoil p Gd n capture on Gd μ capture n from μ capture Gd Recoil p Spallation fast neutron Double-Chooz simulation: μ tracked neutrons tracked 1 neutron created a muon event Far detector: N b <0.5 evt/day (90% C.L.) Near detector: N b <3.2 evts/day (90%C.L.) An outer muon veto will surround it, to tag near miss muons.

37 β-neutron cascades (cosmogenics) μ crossing the detector Likely to be seen by the Veto From Kamland 8 He 9 Li 11 Li β decayed followed by n emission within 100 ms! (not veto-able) μ interaction on 12 C RECONSTRUCT THE μ TRACK (outer veto+inner veto+central detector)

38 Far detector spectrum with PMTs background B/S=5%

39 PMTs background shape rejection: How far? Contours of sensitivity loss

40 Detector definition

41 Mechanics: Acrylics and Buffer Vessel Dimension Distorsion Stress Transport & Integration Inputs : Target : 8 mm γ catcher : 12 m Loads = dead load distortion : <1 mm VM stress: 1 MPa Truck freq. <7 Hz BUT Eigen freq. ~ 8 Hz Impose a precise integration scenario (last gluing on site) Inputs : Buffer : 3 m Loads = 2 kg / pmts + dead load distortion : 4.1 mm VM stress: 23 MPa

42 Mechanics: γ ray shiedling γ s from rock radioactivity dominate the single rate in the Target+GC (no shield) Optimum shielding with 17 cm of low radioactive steel (G3 & G4) Cracks a few % effect 250 tons of steel to be assembled in bars. A 1 cm steel vessel guarantees the veto tightness Will be demagntized in lab

43 Far Detector Integration XXX Starting Starting date: date: Acquisition 03/ / /2006 (2 months) Tank for mass measurement Starting date: 08/2007 (2 months) Glove box for calibration of target liquid sub contractor on site How long? Length of cables 35 meters Painting of inner surface APC (Cylinder transport in 6 half rings) Integration of OUTER VETO Welding Free of 2 area half for cylinders. preparation studies Insertion by translation of the target vessel Rebuilding Side shielding into the gamma of piece of catcher Rotation of the gamma catcher Mounting into cylinders the of detector 534 in the buffer pit PMTs E.M. shield? (vessel and lid) Cleaning after mounting? Closing of buffer vessel Buffer vessel realize with 3 welded rings Closing of the veto vessel Acrylics feet mounting Veto vessel Filling up of the different vessels White painted

44 Goal: Gd doped scintillator development 0.1% Gd loaded scintillator (follow up of LENS R&D) Light yield ~8000 γ/mev + attenuation length > 5m STABLE & Compatible with acrylic Ongoing: / Long term stability 2/ scintillator-acrylic compatibility 400 days Ageing o [x2-4 each 10 0 ] Material compatibility test + acrylic design Gd-Acac 3+ Gd 100 T [%] Gd(2MVA)3 in PC(35%)+Dod(65%) [2MVA]=0.05M [Gd]=2g/l after 1 month after T-test (6 40 C) after T-test (14 days@40 C) after T-test (20 C) λ [nm] R-COO- R-COO- 3+ Gd (R-COOH) x Carboxylate -OOC-R

45 Scintillator status (russia-lngs-heidelberg) Gd-loading: 1g/l solvent: PXE/dodecane (20:80 by vol.) Scintillator development and tests started 2003 Carboxylate scintillator: Beta-Diketonate scintillator: 25 attenuation length [m] wavelength [nm] Light yield: 89 % of unloaded Light yield: 80 % of unloaded

46 Mockups Physical! one in Japan (instrtumented) Mechanical on in france

47 Testing & prototyping

48 Phototubes baseline 8 / 10 Ultra low background tubes 534 / 330 PMTs ~13 % coverage (200 p.e. Mev) Energy resolution goal: 7 % at 1 MeV Current work: PMT selection (size, radiopurity) ETL 9354KB, Hamamatsu, Photonis Angular sensitivity, Concentrators? Magnetic shielding (yes) design study Tilting tube options Cabling & Tightness (done)

49 Electronics & DAQ Hardware digitization 8 channels : Waveform module 125 modules 7 VME crates 18 modules/crate First level trigger (hardware) on single light : coincidences performed by software Trigger: Detect coincidences Detect neutrinolike events (2 singles with E < 50MeV) Keep more data for neutrinolike than for other events Monitoring Artificial triggers: Pulser Laser Fission chamber (neutron source) V1721 developped DC/CAEN Total 11 GB/d

50 Survey Scintillator Stability Double Chooz R&D: 2 generation of Gd-Loaded scintillator 1 st generation < 2004 : Gd-CBX some failures at 20 o C 2 nd generation > 2004 Gd-CBX & Gd-Beta-Dikotonates (Gd-dpm) - Improved stability and optics (suitable for Double Chooz) - R&D finalization phase Validation on ~100 l scale with a Double Chooz mockup UV-VIS-IR scintillator attenuation length - Transition to industrial production (100kg is needed): MPIK Heidelberg is constructing a new building for storage and purification of all scintillators for both detectors. - On-site storage tanks for scintillators in Chooz

51 Calibration Target region: Articulated arm (2-3 cm accuracy) γ-catcher and buffer: Wire driven sources (guide tubes) Simulated detector response for various sources:

52 By products: Non proliferation effort

53 IAEA: International Agency for Atomic Energy Non proliferation effort reactor monitoring Missions: Safety & Security, Science & Technology, Safeguard & Verification Control that member states do not use civil installations with military goals (production of plutonium!) Control of the nuclear fuel in the whole fuel cycle * Fuel assemblies, rods, containers * (*Anti-neutrinos could play a role!) Distant & unexpected controls of the nuclear installations * Why IAEA is interested to antineutrino? IAEA wants the «state of the art» methods for the future! IAEA wants a feasibility study on antineutrinos Monitoring of the reactors with a Double-Chooz like detector? Monitoring a country new reactors à la KamLAND Mini-Inca Double-Chooz-IAEA: Perform new antineutrino spectrum reactor (Mini-Inca + β-spectrometer) Use Double-Chooz near as a prototype for nuclear reactor monitoring Other studies like large and very large underwater antineutrino detectors Collaboration with Los Alamos, Livermore, Sandia

54 Byproducts: geoneutrinos -> Recent kamland result Double Chooz is too small to see them, But can help study the measurement of anti neutrinos

55 10 TW geo-reactor First evidence: kamland Need neutrino direction measurement

56 To find the direction of incoming neutrinos, compare the GLOBAL angular ditribution with MC Chooz first experiment Ex/ : Double Chooz: large numbers of neutrinos with known direction, which will allow to improve algorythm

57 conclusions

58 Discovery potential 1 d.o.f.

59 : Data taking Efficiencies included 1% bin to bin uncorrelated error on background subtraction. 90% C.L. limit if sin 2 (2θ)=0 Δm 2 atm = ev 2 (20% uncertainty) σ sys =2.5% σ sys =0.6% Excluded by CHOOZ Systématiques: - σ abs = 2.0% - σ rel = 0.6% - σ scl = 0.5% - σ shp = 2.0% - σ Δm 2 = 20% Far detector (1km) alone Both detectors 1 km & 280 m Complementary with T2K, Noνa 5y

60 Sensitivity Double-Chooz Far Detector starts in 2007 Double-Chooz Far detector follows 16 months later 90% C.L. contour if sin 2 (2θ)=0 Δm 2 atm = ev 2 is supposed to be known at 20% by MINOS σ sys =2.5% Far detector only Far & Near detectors together σ sys =0.6% 08/

61 Triple Chooz (hep/ ) Old undertground reactor Chooz A being dismantled Large cavities 30x30 m available in Opportunity for an additional >few hundreds tons detector Large cavity 2011 Current neutrino laboratory

62 Possible measurement

63 Experimental context 3σ discovery potential 3σ sensitivity (no signal)

64 Conclusions & outlook Double Chooz ready to go! Moving towards the construction phase Start of the integration Start of phase I : Far 1 km detector alone 1 km sin 2 (2θ 13 ) < 0.06 in 1,5 year World best sensitivity foreseen from 2008? Start of phase II : Both near and far detectors m + 1 km sin 2 (2θ 13 ) < in 3 years Complementarity with Superbeam experiments: T2K, Nova

65 RESERVE

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69 STATUS countries France: accepted Russia : accepted Germany : accepted by Max Planck, DFG in July Spain: joined a few month ago, committee in June USA : in difficult discussion. Supported by HEPAP (public report), but low priority for DOE New countries in discussion Proposal being published the 1 th of June Collaboration meeting Heidelberg November MOU September? Order shielding and PMTs this Summer Start to build the detector in 2007 for data taking in 2 years from now

70 Veto Inner Veto: 100 PMTs Liquid scintillator Tyvek sheets (80 % refl.) x ,1% 3 per cm track length veto region [cm]) Track length in veto of all crossing muons 89,6% of tracks are > 120 cm Outer Veto (Argonne?): gas-filled proportional tubes

71 Collaboration Spain CIEMAT Madrid + Japan (Tokyo Metropolitan Univ, Tohoku Univ., Niigata Univ. ~100 physiciens & ingénieurs

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73 Near laboratory infrastructure Preliminary civil engineering study beginning 2006 Detailed study Autorisation & call for the bid Construction m shaft - Liquid storage area - Buildings & equipements Integration from end of 2009

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75 2001: Neutrinos & θ 13 Three massive neutrinos (3 masses to determine) neutrinos ν e ν μ ν oscillate between active flavors ν e ν ν μ τ 1 = 0 0 c 0 23 s 23 s c c s e iδ s 13 c e 0 13 iδ c s s c ν 1 0 ν 2 1 ν 3 θ atm θ 13, δ θ sol 3 mixing angles & 1 CP phase to be mesured sin 2 (2θ atm ) ~ 1 Atmopsheric ν experiments sin 2 (2θ 13 ) 0,15-0,20 (90% C.L) CHOOZ experiment sin 2 (2θ sol ) ~ 0,8 Solar & Reactor ν experiments Strategic interest contribute to define the experimental program Theoretical for the search interest of a possible understand CP violation neutrino in oscillations the lepton sector link to the leptogenesis -

76 08/2003: The Chooz site 280 m ν ν ν ν ν ν ν ν 1051 m

77 1 km site 280 m site Integration to start mid-2007 μ flux x ~10 ~30 m 1.05 m 300 m.w.e events/y 280 m 80 m.w.e events/y Integration end of 2009 DAPNIA

78 Optimum baseline - 10 tons Target D near D far 3 years, Δm 2 atm = ev 2 Case 1: 10 tons detector target 1.35 km: sin 2 (2θ)<0.018 between 1.1 km and 1.7 km: sin 2 (2θ)<0.02 Case 2: 100 tons detector target Very flat between <1 km and >2 km

79 : Detector design Systematics CHOOZ (2% reactor + 1.5% detector) Double Chooz (0% reactor + 0.6% detector) Target ν : 80% dodecane + 20% PXE +0,1% Gd + PPO + Bis-MSB 7 m γ Catcher : 80% dodecane + 20% PXE + PPO + Bis-MSB Non scintillating Buffer : mineral oil / PMTs Muon Veto : mineral oil PMTs Stainless steel Buffer vessel 7 m Shielding: 17 cm steel

80 An attractive design Double Chooz 2 modules of 8 tons Daya Bay 8 modules of 20 tons (RENO 2 x 8 tons modules)

81 Gd doped scintillator Solvant: 20% PXE 80% Dodecane Gd loading: being & LNGS 0.1% Gd loading Gd-CBX Based on Carboxilic acids (+stabilizers) Gd-Acac & Gd-Dmp Beta Dikitonate Long term Stability LY ~7000 ph/mev: 6 g/l ppo + 50 mg/l Bis-MSB Attenuation length: a few meters at 420 nm Gd-Acac Gd-Dmp 3+ Gd LY~8000 γ/mev L = 5-10 m 3+ Gd R-COO- R-COO- (R-COOH) x -OOC-R Gd-Carboxylate

82 Inner Veto crucial for bkg rejection Tag μ and secondaries Very high ε (~ 99%) Tag near miss μ Veto systems Outer Veto Redundancy for higher rejection power Baseline 50 cm, scintillating mineral oil ~70 PMTs Reflective walls (paint + Tyvek) Outer Veto Depth Outer Veto Neutrons rate Outer Veto Radius Baseline Gas proportional changed for plastic scintillator counters

83 Muon Veto System

84 Testing & prototyping

85 Electronics & DAQ Level 1 trigger (analog sum above 0.5 MeV) Level 2 trigger (2 coincident Level 1 triggers) FIFO ~ 500 (target) (veto) PMTs Event builder (ν-like μ-tagged) Storage HV+Front-End: Single cable for HV + PMT signal Amplification x15 Pulse shape Baseline correction Handle high energy muons Analog Pulse Summation for Level 1 Trigger Zero dead-time DAQ Flash-ADC Wave-form 500MHz 8-bit ADC (few PEs/ch for ν-events) Developed at APC-PCC with CAEN Prototype FADC being tested

86 Target Calibration Estimate relative Near/far detection efficiency to within 0.5% (dominated by neutron cut) Measure relative Near/Far positron energy scale to within 1% Radioactive sources (γ s from MeV to 4.94 MeV & Am-Be and Cf-252 ) & Laser Devices: Target: Articulated Arm 1 cm positioning accuracy CG and Buffer: Wire driven sources (guide tubes) Deployment of laser light sources and Tagged neutron source on z-axis. Target G C Articulated Arm (preliminary) Detector response to e -, e +, γ s Along a radial scan

87 Last Validation Stage: 1/5 mockup Last stage for the validation of the technical choices for the vessels Construction, material compatibility, filling, and the integration of the detector at the Chooz site Total of 2000 l of oil Filling 13/ Stable in the detector - Inner Target: 120 l : 20%PXE+80%dodecane+0.1%Gd - Gamma Catcher: 220 l : 20%PXE+80%dodecane All teflon filling system

88 Systematics Chooz Double-Chooz Reactorinduced Detector - induced ν flux and σ 1.9 % <0.1 % Reactor power 0.7 % <0.1 % Energy per fission 0.6 % <0.1 % Solid angle 0.3 % <0.1 % Volume 0.3 % 0.2 % Density 0.3 % <0.1 % H/C ratio & Gd concentration 1.2 % <0.1 % Spatial effects 1.0 % <0.1 % Live time few % 0.25 % Two identical detectors, Low bkg Distance 10 cm + monitor core barycenter Same weight sensor for both det. Accurate T control (near/far) Same scintillator batch + Stability identical Target geometry & LS Measured with several methods Analysis From 7 to 3 cuts 1.5 % % (see next slide) Total 2.7 % < 0.6 %

89 Relative Normalization: 1.5% syst. err. - 7 analysis cuts - Efficiency ~70% Goal Double-Chooz: ~0.3% syst. err. - 2 to 3 analysis cuts Selection cuts - neutron energy (- distance e+ - n ) [level of accidentals] - Δt (e+ -n) ν e pe + Gd n e + n Δt

90 μ induced backgrounds Recoil μ p Gd n capture on Gd μ capture n from μ capture Gd Recoil p Spallation fast neutron Source Target g - catcher Target g - catcher Buffer Veto 10 -x scintillator scintillator acrylics acrylics liquid liquid K μ Fast Neutrons Full simulation Geant + Fluka Old Chooz simulation MC is reliable! -Simulated: N b =0.8 evts/day - Measured in-situ: N b = ~ 1 evts/day Double-Chooz simulation: - Far detector: N b <2.2 evts/day (90% C.L.) -Near detector: N b <8.9 evts/day (90%C.L.) Accidental Background singles dominated by PMTs neutrons from cosmics single rates: ~1-2 Hz above 0.5 MeV Radiopurity constraints on detector materials single rate <0.1 Hz from each contribution U / / / -11 Th -12 / Less stringent than KamLAND and Borexino, but needs special care

91 Estimation from Chooz Reactor OFF data Total Chooz rate: fast neutrons + 9 Li 2 methods: 1.65(0.49) d -1 & 1.42(0.16) d -1 About half may be 9 Li. n-like Energy (MeV) A Reactor OFF B d e + d n d e + n 30 cm 30 cm 100 cm 2 Δt 100 μs Extrapolation to the Far detector: - Predicted 9 Li rate is ~1.4 d -1 - ~2% of expected signal - To be measured within a few tens of percent D ν candidate region C e + -like Energy (MeV) Extrapolation to the Near detector: Near detector ~20 d -1 events Reactor OFF Chooz data ~0.5% of signal 5 days of Reactor OFF would be sufficient 9-Li flat MeV

92 Backgrounds

93 Analysis

94 Complementarity with Superbeams (3σ discovery potential) Double-CHOOZ starts with 2 detectors in 2008 T2K starts with full intensity in 2010 Δm 2 = ev σ (90% C.L.) 3 σ (99.73% C.L.) sin 2 2θ 13 = 0.08 Reactor experiment can: - Break correlation and degeneracy's - Replace an antineutrino running (second generation) - Accelerate the optimization of future accelerator experiment