Double-CH 13 13 Z
description
Transcript of Double-CH 13 13 Z
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 !
@m2atm=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 PWR
Cores 2
Power 8.4 GWth
Couplage 1996/1997
(%, in to 2000) 66, 57
Constructeur Framatome
Opérateur 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 n
Gd
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-C
OO
-
R-COO- -O
OC-R
Carboxylate
Scintillator developmentVolume
[m3]Type
-target 12,7 0,1% Gd loaded scintillator
-Catcher 28,1 Unloaded scintillator
Buffer 100 Non scintillating oil
Veto 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% GdLY~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 km
e
Spectrum deformation @Double-CHOOZ
sin2(213)=0.15
Double-CHOOZ discovery potential
Th. Lasserre
Double-CHOOZ discovery potential
I
CompareDouble-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-Chooz
Target 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/dFar : 60/d
Near: 3000/d
Number of events 2700Far : 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 » type
Error type CHOOZNew
experiment
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 GdH
H
(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%
Cuts
6<En (MeV)<12
2< n<100sD<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 - - Uncorrelated
11Be 13.80 s 11.5 < 2 < 23 Uncorrelated
11Li 0.09 s 20.8 - - Correlated
9Li + 8He
0.18 s 13.620.3 214
Correlated
0.12 s 10.6 Correlated
8Li 0.84 s 16.0 41 3914 Uncorrelated
6He 0.81 s 3.5 141 15516 Uncorrelated
+, EC
11C 20.38 m 0.96 77049 8765562 Uncorrelated
10C 19.30 s 1.9 9812 1118141 Uncorrelated
9C 0.13 s 16.0 41 4715 Uncorrelated
8B 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