Transcript Slide 1

Double-CH1313Z
H. De Kerret (APC)
On behalf the Double-Chooz proto-collaboration
June 9 2004
Best current constraint: CHOOZ
R = 1.01  2.8%(stat)2.7%(syst)
e  e (disappearance experiment)
Pth= 8.5 GWth, L = 1,1 km, M = 5t
overburden: 300 mwe
World best constraint !
e  x
@m2atm=2 10-3 eV2
sin22θ13 < 0.2
(90% C.L)
M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374
The Double-CHOOZ concept
e
e,,
D1 = 100-200 m
CHOOZ power station

Near detector
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
D2 = 1050 m
Far detector
CHOOZ site
&
Detector Overview
e
Double-Chooz, Ardennes, France
Type
PWR
Cores
2
Power
8.4 GWth
Couplage
1996/1997
(%, in to 2000)
66, 57
Constructeur
Framatome
Opérateur
EDF
Chooz-Near
Chooz-Far
Near site: D~100-200 m, overburden 50-80 mwe
Far site: D~1.1 km, overburden 300 mwe
V=2 x 12,67 m3, Dp=100-200m, Dl=1050m
The CHOOZ-near site
Near detector @100-200 m from the cores
Exact position under study, in collaboration with EDF
250 m
125 m
Detect the antineutrino
e + p

e+ + n
Correlations:
- time :   30s
- space 3e : < 1m3
511 keV

e+
511 keV
p
  - 8 MeV
n
Gd
• Energy measurement
of the e+, => E
• Neutron capture
on Gd, ED≈8 MeV
The target is the active medium :
- liquid scintillator loaded at ≈ 0.1 % en Gd
Important progress from LENS
The CHOOZ-near detector
~10-20 m
Dense material
Distance
Reactor-detector
Overburden (m.w.e)
100
45-53
150
55-65
200
67,5-80
~5- 15 m
Detector design
• A scintillating buffer around
the target (to see the gammas
from positron capture and Gd
decays) ~60 cm
• A non scintillating buffer
in 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
7m
shielding: 0,15m steel
 target:80% dodécane + 20% PXE + 0.1% Gd
(acrylix, r=1,2m, h = 2,8m, 12,7 m3)
-catcher: 80% dodécane + 20% PXE
(acrylique, r+0,6m – V= 28,1 m3)
7m
non-scintillating buffer: same liquid (+ quencher?)
(r+0.95m, , V=100 m3)
7m
Existing pit
PMTs supporting structure
Muon VETO: scintillating oil
(r+0.6 m – V=110 m3)
Scintillator Overview
Gadolinium doped scintillator
Goal: 0.1% Gd loaded scintillator
Light yield ~8000 /MeV + attenuation length > 5m
STABLE
Compatible with acrylic
R&D LENS 1998-2004
•Carboxylate based scintillator
•Beta dikitonates based scintillator
3+Gd
(R-COOH)x
Gd-Acac
R-COO-
3+Gd
Carboxylate
Scintillator development
Gd-ACAC
Volume [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)
Flours concentration
- Match scintillation light to PMTs
- PPO : 6g/l
- BisMSB: 20mg/l
Baseline: 80% dodecane + 20% PXE + 6 g/l PPO + 20 mg/l BisMSB + 0.1% Gd
LY~8000 /MeV , L = 5-10 meters
Scintillator R&D
 R&D
 2004
1/ Long term stability
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
Analyse standard
Expected events / bin i: NiA( sin2(213)gen )
Tested spectrum OiA:
Theoretical prediction : TiA= (1 + a + bA + ci) x NiA( sin2(213)rec )
σ abs  0.02
σ b2b  0.01
σ rel  0.006
Rate bkg  0.01
σ bkg  1.0
90% C.L. sensitivity if sin2(213)=0
m2=2.0 10-3 eV2
3 years (efficiency included)
sin2(213)<0.03
m2=2.4 10-3 eV2
3 years (efficiency included)
sin2(213)<0.024
Relative normalisation error
m2=2.0 10-3 eV2
3 years (efficiency included)
Influence of flat backgrounds
Th. Lasserre
Influence of the shape error
Th. Lasserre
Lindner’s analysis of Double-CHOOZ sensitivity
Lindner’s analysis of Double-CHOOZ sensitivity
12.7 tons, 3 years
P. Huber et. al. hep/0403068
340 tons, 3 years
e
Attempt to compare Double-Chooz
with Beams & Superbrams
m2=2.0 10-3 eV2
P. Huber et. al. hep/0403068
Double-CHOOZ starts with two detectors on 01/01/2008
T2K starts at FULL intensity on 01/01/2010
e oscillation @Double-CHOOZ
@1,05 km
e
Spectrum deformation @Double-CHOOZ
sin2(213)=0.15
Double-CHOOZ discovery potential
Th. Lasserre
Double-CHOOZ discovery potential
Compare
I
Double-Chooz & T2K (limite @90% C.L.)
Attempt to compare Double-Chooz with
T2K (3σ discovery potential)
22θ
sin
22θ
13 = 0.08
sin
sin22θ
0.04
1313= =0.14
Energy scale
Energy scale modified on both detectors by +1%
Use a 1 parameter fit for all the rest
13(fit)
Strong distortion
13(gen)
Position of the near detector
Moving the Close detector by +0.5m
Distance to reactor increases
Dist to Far decreases
Burn-up effect (330 days fuel evolution)
First day
day 330
 (fit)
235U
239Pu
238U
241Pu
 (gen)
Proto-collaboration,
Letter of Intent
and 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 atmosphere
Cost 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 -
@CHOOZ: R = 1.01  2.8%(stat)2.7%(syst)
 increase luminosity L = t x P(GW) x Vcible
CHOOZ
Double-Chooz
5,555 m3
12,67 m3
6,77 H/m3
6,82 H/m3
quelques mois
3-5 years
Rate
26/d
Far : 60/d
Near: 3000/d
Number of events
2700
Far : 60 000/3 years
Near: >3 106/3 years
Erreur stat
2,7%
0,4%
Target volume
Number of free protons
Data taking
Improve CHOOZ
– Systematic error @CHOOZ : σsys=2.8%
 Decrease the total systematic error
1. Detector design
2. 2 identical detectors  vers σrelative sys~0,6%
3. Background – improve S/B>100  error<1%
Detector simulation
&
calibration
Photons tracking
2 simulation indépendantes
• PCC & APC  simulation de CHOOZ (GEANT3)
• Kurchatov  simulation Borexino (GEANT4)
Photons tracking
 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)
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
Systematic errors
Systematic error; « reactor » type
Réacteur
Error type
CHOOZ
New
experiment
Double-Chooz
Cross section
Antineutrinos
Thermal power
E/Fission

0.2%
1.9%
0.7%
0.6%
2.1%
0.2%
<1.9%
<0.7%
<0.6%
~2.1%
O(0.1%)
O(0.1%)
O(0.1%)
O(0.1%)
O(0.1%)
Systematic errors: « detector » type
Detector
Error type
CHOOZ
solid angle
Scintillator density
%H
Target
«Spill in/out»
Dead
0.3%
1.2%
0.3%
1.0%
?
New
experiment
0.2%
0.1%
<1%
0.2%
1.0%
0.25%
M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374
Double-Chooz
0.2%
O(0.1%)
O(0.1%)
0.2%
O(0.1%)
<0.25%
Same batch of scintillator
for both detectors
Fast signal: positron
Non scintillating Buffer
scintillanting buffer
Ee+ (MeV)
Ee+ (MeV)
• 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
Non scintillating buffer
H
Scintillating buffer
Gd
Gd
H
En (MeV)
(H. de Kerret)
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
Analyis cuts @CHOOZ
Erreur
e+ seuil
e+/géode (30cm)
n capture
Neutron énergie
Distance n-géode (30 cm)
Distance (e+-n)
t (e+-n)
n multiplicity

CHOOZ
0.8%
0.1%
1.0%
0.4%
0.1%
0.3%
0.4%
0.5%
1.5%
M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374
Analysis cuts @Double-CHOOZ
Cuts
6<En (MeV)<12
2< n<100s
D<1-2m
Error type
Distance (e+-n)
En
t (e+-n)

CHOOZ
0.3%
0.4%
0.4%
-
Double-CHOOZ
0 - 0.2%
0.2%
0.1%
0.2-0.3%
Used or not ?
Calibration Cf
electronics
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
Reduce backgrounds
- 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 buffers
Double-Chooz: B/3  less than 0.5% and measurable
-correlated events:
CHOOZ: ~1 recoil proton / day & signal =26/d
Double-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%
Accidental Ibackground
S/B>103
S/B=350
Spallation neutrons
• 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

Surrounded by 100 mwe rock shielding
Muon induced production of radioactive isotope
-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.)
-
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
+
8He
0.18 s
13.6
0.12 s
10.6
20.3
214
8Li
0.84 s
16.0
41
3914
Uncorrelated
6He
0.81 s
3.5
141
15516
Uncorrelated
11C
20.38 m
0.96
77049
8765562
Uncorrelated
10C
19.30 s
1.9
9812
1118141
Uncorrelated
9C
0.13 s
16.0
41
4715
Uncorrelated
8B
0.77 s
13.7
61
6914
Uncorrelated
7Be
53.3 d
0.48
19620
2228223
Uncorrelated
9Li
 +,
EC
• Rates are given for the CHOOZ 10 t PXE case (C16H18)
Correlated events
Dominated by -n cascade, ~few 100ms
Li9/He8(Kamland?)
8He, 9Li, 11Li
(instable isotopes)
 to know: the ratio
,
trigger on the other branch of Li9 (M.Cribier: 2 betas >3 MeV)
measure li9 between 8 MeV and 11.9MeV
 the shapes
Correlated
Correlated
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