Double-CH1313Z H. De Kerret (APC)

On behalf the Double-Chooz proto-collaboration

June 9 2004

e e (disappearance experiment)

Pth= 8.5 GWth, L = 1,1 km, M = 5toverburden: 300 mwe

Best current constraint: CHOOZ

World best constraint !@m2

atm=2 10-3 eV2

sin22θ13 < 0.2

(90% C.L)

ex

R = 1.01 2.8%(stat)2.7%(syst)

M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374

The Double-CHOOZ concept

CHOOZ power station Near detector Far detector

D1 = 100-200 m

D2 = 1050 m

e e,,

anti-e flux (uranium 235, 238 & plutonium 239, 241) Reaction: e + p e+ + n, <E>~ 4 MeV, Ethresholdl =1.8 MeV Dissapearance experiement Search for a departure from the 1/D2 behavior

CHOOZ site &

Detector Overview

e

Near site: D~100-200 m, overburden 50-80 mweFar site: D~1.1 km, overburden 300 mwe

Type PWRCores 2Power 8.4 GWth

Couplage 1996/1997

(%, in to 2000) 66, 57Constructeur Framatom

eOpérateur EDF

V=2 x 12,67 m3, Dp=100-200m, Dl=1050m

Chooz-Far

Chooz-Near

Double-Chooz, Ardennes, France

The CHOOZ-near site

250 m

125 m

Near detector @100-200 m from the coresExact position under study, in collaboration with EDF

Detect the antineutrino

e+

p nGd

511 keV

511 keV 8 MeV• Energy measurement of the e+, => E • Neutron capture on Gd, ED≈8 MeV

Correlations:- time : 30s- space 3e : < 1m3

The target is the active medium :- liquid scintillator loaded at ≈ 0.1 % en Gd

Important progress from LENS

e + p e+ + n

The CHOOZ-near detector

~5- 15 m

Dense material

~10-20 m

DistanceReactor-detector

Overburden (m.w.e)

100 45-53

150 55-65

200 67,5-80

Detector design

• A scintillating buffer around the target (to see the gammas from positron capture and Gddecays) ~60 cm• A non scintillating bufferin front of pmts (reduce the single rates) ~ 1m• A muon veto • Increase as much as possible the active buffer for the fast neutrons coming from outside

The CHOOZ-far detector

Existing pit

non-scintillating buffer: same liquid (+ quencher?)(r+0.95m, , V=100 m3)

-catcher: 80% dodécane + 20% PXE (acrylique, r+0,6m – V= 28,1 m3)

7 m

7 m

PMTs supporting structure

Muon VETO: scintillating oil (r+0.6 m – V=110 m3)

7 m

shielding: 0,15m steel

target:80% dodécane + 20% PXE + 0.1% Gd (acrylix, r=1,2m, h = 2,8m, 12,7 m3)

Scintillator Overview

Goal: 0.1% Gd loaded scintillatorLight yield ~8000 /MeV + attenuation length > 5mSTABLE Compatible with acrylic

R&D LENS 1998-2004 •Carboxylate based scintillator•Beta dikitonates based scintillator

Gadolinium doped scintillator

Gd-Acac

3+Gd3+Gd(R-CO

OH

)x R-CO

O-

R-COO- -OOC-R

Carboxylate

Scintillator developmentVolume

[m3] Type

-target 12,7 0,1% Gd loaded scintillator-Catcher 28,1 Unloaded scintillatorBuffer 100 Non scintillating oilVeto 110 Scintillating oil

Baseline- PC (C9H12), PXE (C16H18) attack acrylics- Dodécane + PXE more resistant …- R&D Saclay+MPIK+Gran Sasso (08/2004)Baseline: 80% dodecane + 20% PXE + 6 g/l PPO + 20 mg/l BisMSB + 0.1% Gd

LY~8000 /MeV , L = 5-10 meters

Flours concentration- Match scintillation light to PMTs - PPO : 6g/l- BisMSB: 20mg/l

Gd-ACAC

Scintillator R&D R&D 1/ Long term stability 2004 2/ scintillator-acrylic compatibility Ageing test @50o (Saclay , Gran Sasso/INR, MPIK) Material compatibility test (Saclay , MPIK) Saclay acrylic envelop design in progress

(scintillator tests, Saclay) First ageing test @40o, 50o

(Caroxylates, Gran Sasso / INR)

Sensitivity &

Discovery Potential

Description of the simulation

0.02σabs

0.006σ rel

0.01σb2b

1.0σbkg 0.01Ratebkg

Analyse standard

Expected events / bin i: NiA( sin2(213)gen )

Tested spectrum OiA:

Theoretical prediction : TiA= (1 + a + bA + ci) x

NiA( sin2(213)rec )

90% C.L. sensitivity if sin2(213)=0

m2=2.0 10-3 eV2

3 years (efficiency included) sin2(213)<0.03

m2=2.4 10-3 eV2

3 years (efficiency included) sin2(213)<0.024

Relative normalisation error

m2=2.0 10-3 eV2

3 years (efficiency included)

Th. Lasserre

Influence of flat backgrounds

Th. Lasserre

Influence of the shape error

Lindner’s analysis of Double-CHOOZ sensitivity

Lindner’s analysis of Double-CHOOZ sensitivity

e

12.7 tons, 3 years 340 tons, 3 years

P. Huber et. al. hep/0403068

Attempt to compare Double-Chooz with Beams & Superbrams

P. Huber et. al. hep/0403068

Double-CHOOZ starts with two detectors on 01/01/2008T2K starts at FULL intensity on 01/01/2010

m2=2.0 10-3 eV2

e oscillation @Double-CHOOZ

@1,05 kme

Spectrum deformation @Double-CHOOZ

sin2(213)=0.15

Double-CHOOZ discovery potential

Th. Lasserre

Double-CHOOZ discovery potential

ICompare

Double-Chooz & T2K (limite @90% C.L.)

Attempt to compare Double-Chooz with T2K (3σ discovery potential)

sin22θ13 = 0.14 sin22θ13 = 0.08 sin22θ13 = 0.04

gen

(fit)

Energy scale modified on both detectors by +1%

Strong distortion

Use a 1 parameter fit for all the rest

Energy scale

Position of the near detector

Moving the Close detector by +0.5m

Distance to reactor increasesDist to Far decreases

235U

239Pu

238U241Pu

fit

gen

Burn-up effect (330 days fuel evolution)

First day

day 330

Proto-collaboration, Letter of Intentand prospects

e

The current proto-collaboration

Chooz, November 2003

Double-CHOOZ meetings • Chooz, November 2003• Heidelberg, February 2004• Tubingen, April 2004

Letter of Intent

Double-Chooz & IAEA IAEA :Intenational Agency for Atomic Energy

Missions: Safety & Security, Science & Technology, Safeguard & Verification Control that member states do no 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 !

Several futuristic methods under study Kr, I, Cs gas trace in atmosphereCost issue …

AIEA wants a feasibility study on antineutrinos- Monitoring of the reactors with a Double-Chooz like detector ?- Monitoring a country – new reactors “à la KamLAND”

CEA/Saclay we already ask some support for:

- Double-Chooz near detector - New nuclear physics program to improve knowledge of reactor spectrum

Improving CHOOZ – Statistical error -

increase luminosity L = t x P(GW) x Vcible

@CHOOZ: R = 1.01 2.8%(stat)2.7%(syst)

CHOOZ Double-ChoozTarget volume 5,555 m3 12,67 m3

Number of free protons 6,77 H/m3 6,82 H/m3

Data taking quelques mois 3-5 years

Rate 26/d Far : 60/dNear: 3000/d

Number of events 2700 Far : 60 000/3 yearsNear: >3 106/3 years

Erreur stat 2,7% 0,4%

Decrease the total systematic error

1. Detector design2. 2 identical detectors vers σrelative sys~0,6%3. Background – improve S/B>100 error<1%

Improve CHOOZ – Systematic error -

@CHOOZ : σsys=2.8%

Detector simulation&

calibration

Photons tracking

2 simulation indépendantes

• PCC & APC simulation de CHOOZ (GEANT3)• Kurchatov simulation Borexino (GEANT4)

Photons tracking

X[cm]

Y [cm]

Z [cm] Yield[%]

0 0 0 100

0 60 0 101,0

0 120 0 102,5

0 180 0 109,6

0 60 140 102,3

0 120 140 103,5

0 150 170 104,8

0 180 200 107,7

20% PXE + 80% dodécane + 0.1% Gd + 6g/l PPO + 20mg/l BisMSB

~200 p.e./MeV with 500 PMTs – reflection coef =0%

Les PMs 8’’ are within the buffer ( glass at 25 cm inside)

Light collection ~flat (+5% maxi. in the target)

Systematic errors

Systematic error; « reactor » type

Error type CHOOZNew

experiment

Double-Chooz

Réacteur

Cross section 0.2% 0.2% O(0.1%)Antineutrinos 1.9% <1.9% O(0.1%)

Thermal power 0.7% <0.7% O(0.1%)E/Fission 0.6% <0.6% O(0.1%)

2.1% ~2.1% O(0.1%)

Systematic errors: « detector » typeError type CHOOZ

New experime

nt Double-Chooz

Detector

solid angle - 0.2% 0.2%Scintillator density 0.3% 0.1% O(0.1%)

%H 1.2% <1% O(0.1%)Target 0.3% 0.2% 0.2%

«Spill in/out» 1.0% 1.0% O(0.1%)Dead ? 0.25% <0.25%

M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374 Same batch of scintillator for both

detectors

Fast signal: positron

Ee+ (MeV)Ee+ (MeV)

Non scintillating Buffer scintillanting buffer

• CHOOZ : only scintillanting buffer • Detector = calorimter : positron energy is fully contained • But accidental rate high threshold on e+, many analysis cuts

• Double-CHOOZ : 1 Scintillanting buffer (60cm) + 1 Non-scintillanting buffer (95cm)

• Reduce the PMTs noise (40K,Tl)• Eseuil hardware ~500 keV No more thrshold cut 0% systematic ! • 1.022 MeV calibration point at e+ spectrum start ( )• BDFs measuremnt above and below the positiron spectrum

Delayed signal : neutron

Gd GdHH

(H. de Kerret) En (MeV)En (MeV)

Gadolinium loaded scintillator (~0.1%) • Gd 8 MeV ’s (capture on Gd : 86.6%1.0% in CHOOZ, Eur.Phys.J. C27 (2003) 331-374) • H 2.2 MeV ’s• n capture prob. 1.0% (CHOOZ) O% with 2 detectors (MC uncertainty)• t (e+-n) 0.4% (CHOOZ) 0% with 2 detectors (MC uncertainty)

n energy 0.4% (CHOOZ) Scintillating buffer mandatory (as in CHOOZ)“spill in / spill out” effect 1.0% (CHOOZ) O(0.1%) 2 identical detectors needed!

But neutronics to be checked

Non scintillating buffer Scintillating buffer

Erreur CHOOZ e+ seuil 0.8%

e+/géode (30cm) 0.1% n capture 1.0%

Neutron énergie 0.4% Distance n-géode (30 cm) 0.1%

Distance (e+-n) 0.3%t (e+-n) 0.4%

n multiplicity 0.5% 1.5%

M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374

Error type CHOOZ Double-CHOOZ Distance (e+-n) 0.3% 0 - 0.2% Used or not ?

En 0.4% 0.2% Calibration Cft (e+-n) 0.4% 0.1% electronics

- 0.2-0.3%

Cuts6<En

(MeV)<122< n<100s

D<1-2m

Analysis cuts @Double-CHOOZ

Analyis cuts @CHOOZ

All systematic errors in Double-Chooz

R&D on systematic errors in 2004• Dead time (Heidelberg) - important (~50%) but simple (500microsec/muon) - generate couples of test particles et measure their survival time - hardware tests in 2004

• Quantity of liquid in the target (Saclay) - build both targets in factory in the same time + test filling - geometrical measurements in factory and on site - weight liquids in the same intermdiate tank 0.1%

• Distance detector-reactor core(APC-Saclay ph.nucl.+Subatech?) -10cm a 150 m 0.15% systematic error - 10cm in Chooz pub. (+- 3cm at Bugey) - core center of gravty movement of 6cm monitored at bugey

Background

- CHOOZ: S/B ~ 25 - Double-CHOOZ aim: S/B>~100

- Double-CHOOZ-far (300 mwe): 12.7 m3 Signal x ~3

-Accidentals: Buffer non scintillanting buffersDouble-Chooz: B/3 less than 0.5% and measurable

-correlated events: CHOOZ: ~1 recoil proton / day & signal =26/dDouble-CHOOZ: S* 2.3 & B/2 S/B>100 (neutronn simulation in progress)

-Double-CHOOZ-near (~60 mwe): Signal x 50-100 SCHOOZ-loin

-Dproche ~100-200m Signal * >30, but * 30

- all backgrounds:BDF CHOOZ-loin * <30 S/B > 100

Measure all BDFs at 50%

Reduce backgrounds

IAccidental background

S/B=350

S/B>103

Spallation neutrons

Surrounded by 100 mwe rock shielding

• Simulation of neutrons from near-miss (Geant4) Neutron produits dans la roche et transportés jusqu’au détecteurs (Fluka)

• Liquid buffers rejection • Double-CHOOZ-far : simulation <2/day Double-CHOOZ-near : thicker VETO

Muon induced production of radioactive isotope

Isotope T1/2 Emax (MeV)

Rate (day-1)300 mwe

Rate (day-1)20 m (50 mwe)

Type

-

12B 0.02 s 13.4 - - Uncorrelated11Be 13.80 s 11.5 < 2 < 23 Uncorrelated11Li 0.09 s 20.8 - - Correlated

9Li + 8He

0.18 s 13.620.3 214

Correlated0.12 s 10.6 Correlated

8Li 0.84 s 16.0 41 3914 Uncorrelated6He 0.81 s 3.5 141 15516 Uncorrelated

+, EC

11C 20.38 m 0.96 77049 8765562 Uncorrelated10C 19.30 s 1.9 9812 1118141 Uncorrelated9C 0.13 s 16.0 41 4715 Uncorrelated8B 0.77 s 13.7 61 6914 Uncorrelated

7Be 53.3 d 0.48 19620 2228223 Uncorrelated

• Rates are given for the CHOOZ 10 t PXE case (C16H18)

-Background: Production of radioactive nuclei on 12C in the scintillator-NA54: Isotope production on 12C target @SPS/CERN, beam @100/190 GeV (E) E0.73 (T. Hagner et. al.)

Correlated events Dominated by -n cascade, ~few 100ms 8He, 9Li, 11Li (instable isotopes) to know: the ratio Li9/He8(Kamland?) , trigger on the other branch of Li9 (M.Cribier: 2 betas >3 MeV) measure li9 between 8 MeV and 11.9MeV the shapes

calibration

Same source used in both detectors• gammas 1% de différence between the 2 energy scale 100 KeV at 6 MeV (0.2% systematic)• Cf (neutron multiplicity) <0.2% difference between the 2 neutron efficiencies

• Laser + fibres optical fiber pm stability, absorption length full scan of the target volume

Conclusion Détector and technology known (CHOOZ, BOREXINO, KamLAND, … Few R&D:

liquid scintillator, cibles, systematic errors

Proto-collaboration: Saclay,Nantes, APC, TUM, MPIK, Tubingen,Hambourg, Kurchatov, RAS, Italy ,……… Letter of Intent proposal fall 2004 Strong involvement of EDF (support of the plant management to get funding from the company direction) Detector cost: estimated to 7.25 Meuros ( without the civil engineering of the near detector)

Approved in France (IN2P3 and CEA/saclay) 2-2.5 Meuros ( without the civil engineering of the near detector)

install the far detector in2006 & full data taking in early 2008