Christian Buck, MPIK Heidelberg
description
Transcript of Christian Buck, MPIK Heidelberg
Christian Buck, MPIK Heidelberg
LAUNCH 09
November, 11th 2009
The Double Chooz reactor neutrino
experiment
Neutrino oscillations
3
2
1
321
321
321
UUU
UUU
UUU eeee
Δmsol2 ~ 7.6∙10-5 eV2, sin2(2Θ12) ~ 0.85
Δmatm2 ~ 2.4∙10-3 eV2, sin2(2Θ23) ~ 1
ν2
Δmatm2
Δmsol2
ν1
ν3
sin2Θ13
sin2Θ23
sin2Θ12
νe
νμ
ντ
E
LmPee 4
sin2sin12
13213
2
Why Double Chooz?
Improved knowledge of mixing matrix
Key experiment to unveil leptonic CP violation
Discovery potential: hint given by global analysis
Fogli et al., arXiv:0905.3549 (2009)
Complementarity to beam experiments
- Degeneracies + parameter correlations
- Optimize future accelerator experiments
Discrimination power of 0νββ
Safeguard applications,…
)1(04.008.02sin 132
Reactor neutrino experiments
1956: First observation (Nobel Prize 1995)
1990s: Chooz, Palo Verde (sin22Θ13< 0.2)
2002: KamLand
Δm12, Θ12
Reactor neutrinos: Pure νe - beam Intense flux (~2% precision) Detection: inverse β-decay Energy: few MeV
Double Chooz collaboration
Spokesman: H. de Kerret (APC) France: CEA Saclay, APC Paris, Subatech Nantes, IPHC Strasbourg Germany: MPIK Heidelberg, TU München, EKU Tübingen, Universität Hamburg,
RWTH Aachen USA: Univ. of Alabama, Argonne Nat. Lab., Chicago, Drexel, Kansas State, LLNL,
Notre Dame, Tennessee, Columbia Univ., Davis, MIT, Sandia Spain: CIEMAT Madrid Japan: Tohoku University, Kobe University, Tokyo Inst. of Tech., Niigata
University, Tokyo Metropolitan University, Hiroshima Inst. of Tech. England: University of Sussex Russia: RAS Moskau, Kurchatov Institute Brasil: CBPF Rio de Janeiro, UNICAMP
The Double Chooz principle
Survival probability
G. Mention (APC)
Dnear Dfar
E
Lm
E
LmPee 4
sin2sincos4
sin2sin12
12212
213
42
13213
2
Survival probability assuming sin2(2Θ13) = 0.2 for different Δm13
Current proposals
Angra
Double-Chooz
KaskaDaya bay
RENO
Neutrino signal
n
ep
511 keV511 keV e+
~ 8 MeV
Gd
Target: Gadolinium loaded liquid scintillator
Neutrino rates: - far: ~50/day- near: ~300/day
235U
ββ
236U
n pure e source
Eν ~ MeV
Emin ~ 1.8 MeV
> 1020 /(s∙GW) Chooz: ~ 7.4 GWth
prompt
delayed (30 µs)
Background
Accidentals
n
~ 8 MeV
+
E ≥ 1 MeV
Gd
n
~ 8 MeV
Gd
fast neutrons
β-n-cascades: 9Li,8He
Chooz data:
far detector: ca. 1.4/day
Long lived!
Detector Design
TARGET (2.3m)- Acrylic vessel (8mm)- 10,3 m3 LS (1 g/l Gd)
γ-catcher (0.55m) - Acrylic vessel (12mm)
- 22,6 m3 LS
Buffer (1.05m) -Steel (3 mm)- 110 m3 oil
Inner Veto (0.5m) -Steel (10 mm)
- 80 m3 LS
7m
Calibration systems
Target
GC
Buffer
Articulated arm
z-axis system (glove box)
Guide tube / wire sources
LED system / multi-wavelength
Buffer tube
Comparison with Chooz
Fehler Chooz DC
Statistical 2.8% 0.4%
Flux, σ 1.9 % <0.1 %
E/fission 0.6 % <0.1 %
power 0.7 % <0.1 %
# protons 0.8 % 0.2 %
Det.eff. 1.5 % 0.5 %
Σ System. 2.7 % ~ 0.6%
Best limit: CHOOZ
sin2(2θ13) < 0.15 (90% CL)
for m2atm = 2.5·10-3 eV2
R = 1.01 2.8%(stat) 2.7%(syst)
Reactor
Detector
Sensitivity
2010
Sensitivity 2010 – 2015 (near detector starts < 2 y after far) for m2
atm = 2.8·10-3 eV2
Far detector filling early 2010!
Far detector installation
Lab cleaning
Installation Veto and Veto-PMTs Installation Buffertank
PMT installation
Acrylic vessel installation
Arrival Gamma Catcher on-site Acrylic vessels in lab
Gamma Catcher installationGamma Catcher transport
Status October ‘09
Status near detector
Tunnel (155 m), 12%
Site engineering study completed excavate 2010
r = 415 m (115 m w.e.)
Myons (Veto): 250 Hz reactors
near detector
LaboratoryOpen ramp (85 m), 14%
Liquid storageData taking: 2011
Scintillator development (MPIK)
Requirements:
Gd-solubility > 1 g/l
Stability (5 years)
Transparency
Material compatibility
Radiopurity
Target – Gamma catcher matching (optics + density)
Large scale (multi tons)
Light yield
PXE conc,
PPO conc.
Scintillator properties
400 420 440 460 480 500 520 540 560 580 6000,000
0,005
0,010
0,015
0,020
0,025
0,030
2.5m
5m
abso
rban
ce (1
0 cm
cel
l)
wavelength [nm]
30Aug2006 04Feb2009
10m
Target
Gamma Catcher candidates
Event localization by pulse shape analysis
Transparency in ROI stable in 10 m range!
Time [ns]
Eve
nts
All components (40 tons) delivered to MPIK Purifications finalized, prepare for mixing Scintillator production starts
Large scale production
PMT activities at MPIK
Testing / Calibration Assembly / Installation Implementation of data in Double Chooz software Current upgrade: full detector segment
PMT calibration
Calibration program: HV scans Single photon electron (P/V) Transit time Dark rate Quantum efficiency
Summary
Goal of Double Chooz reactor neutrino experiment: Determination of mixing angle Θ13 (sin2(2θ13) ~ 0.03)
2-detector concept to reduce systematical error
Detection via inverse β-decay in Gadolinium loaded liquid scintillator
Schedule:
– Data taking far detector: Spring 2010
– Near detector: end of 2011
MPIK: scintillators, PMTs, Analysis
Θ13 and 0νββ
Normal hierarchy: discrimination power of 0νββ-exp. depends on sin2(2Θ13) !
M.Lindner, A.Merle, W.Rodejohann, Phys.Rev.D73:073012 (2006)
Positron spectrum
Far/Near ratio
sin2(213)=0.12
e+ spectrum
Far DetetectorStat. Errors
Sensitivity (rate vs shape)
Robustness