demande anr stereo pablo del amo sanchez henri pessard 18/12/2012
TRANSCRIPT
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Overview
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• Neutrino anomalies• The STEREO experiment• ANR request• LAPP’s contribution• Conclusions
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Open questions inoscillation physics
• Oscillations extremely successful description of ν flavour change during propagation, θ13 just measured!
• Mass hierarchy and leptonic CP in ~ 2025 (LAGUNA/LBNO)• Meanwhile, some open questions:
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Anomaly Type Significance
Gallium νe disappearance 2.7σ
Reactor νe disappearance 3.0σ
LSND νμ → νe 3.8σ
MiniBoone νμ → νe 3.0σ
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Gallium anomaly
• GALLEX and SAGE experiments looked for low energy solar neutrinos using Gallium-based detectors (νe+71Ga → e–+71Ge)
Deficit observed during calibration runs:Robs/pred=0.86±0.05 (Bahcall’s σν)
Detectors calibrated with ~MCi νe sources
0.86
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Reactor anomaly• Reactor ν spectrum predicted from β spectrum → compare w/ experiment
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Emitted b spectra per fission
ν spectra per fission
THEORY!!!
Comparison
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Reactor anomaly
• Reactor antineutrino flux re-evaluated (2011): +3.5%
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•Neutron lifetime decrease → σν(InverseBeta Decay) increase +1%•Previously non-accounted long-livedisotopes in reactors +1%
Phys.Rev. C83 (2011) 054615 & Phys.Rev. C84 (2011) 024617
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Reactor anomaly
• → Re-analyse reactor neutrino experiments• Result: 7% less events than expected! (3.0 σ)
• Can be explained with a sterile neutrino with Losc ~ 2-10m
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Robs/pred=0.927±0.023
Phys.Rev. D83 (2011) 073006
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Reactor+Ga anomalies fit
• Both reactor and Ga anomalies can be explained by 1 sterile ν
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Δm2 ~ 2 eV2
sin2(2θee) ~ 0.2Losc ~ 7m
Phys.Rev. D83 (2011) 073006
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Future experiments• Several reactor (short term), sources (short term) & accelerator
(mid-term) experiments under consideration• Probe Reactor+Ga anomalies and sterile ν at the same time:
– Measure rate of reactor– Look at L/E dependence close to reactor (L ~ Losc ~ 10 m)
• Reactor core size important – large cores wash out oscillation
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Grenoble’s ILL most compact!
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STEREO• 2m3 Gd-doped liquid scintillator detector 8m away of ILL reactor
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP,
UniSavoie
• Signature: νe+p→e++n• Segmented target to see L/E dependence at different L’s
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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STEREO• STEREO should see sterile ν oscillation if it’s there• Good performance compared to competition (timing important!)• Liquid scintillator technology well known (DoubleChooz, Nucifer)• Potentially big impact• Cheap : ~ 1,5 M€• Quick experiment!• Timeline:11/2012 ILL Scientific Committee2013-2014 Design & construction2015 Installation at ILL2015-2016 Physics Run
• ergewqrg
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Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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STEREO Collaboration
• ILL, host laboratory: site characterisation.• Three French laboratories:
– CEA Saclay: Inner detector– LAPP: Radioactive source calibration system + possibility of
mechanics of shielding– LPSC: Acquisition electronics + µ veto + shieldings (workshop)
• Foreign collaborators:– Germany, TUM & Max-Plank-Institut Heidelberg: Liquid scintillator +
LED calibration system– Morocco, University Hassan II & CNESTEN.
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Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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ANR Proposal
• Porteur: David LHUILLIER (CEA Saclay)• 800 k€ + 2 postdocs (+1 ENIGMASS postdoc => 1postdoc/french lab)• Timescale:
04/2013 ANR funding decision2013-2014 Design & constructionLate 2014 Lab tests2015 Installation at ILL2015-2016 Physics Run
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Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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LAPP’s contributionCalibration system with radioactive sources
γ sources (Na, Co, n capture by H & Gd)+ n sources (Am-Be)
• Mechanics + automatism + workshop– In touch with B. Lieunard– ITA manpower under
evaluation, seems feasible
• Possibility of engineeringshielding support under study
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m-veto - water
10 c
m le
ad fr
ont w
all Polyethylene
5 target cells40 cm thick
10 cm lead
~ 3.30 m
20 cm acrylic buffer
Tube
Source
Conseil Labo Demande ANR STEREO Pablo DEL AMO SANCHEZ, LAPP, UniSavoie
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Conclusions
• Strong international interest in neutrino anomalies• Grenoble’s ILL unique for Reactor+Gallium anomalies• STEREO has the potential to address Reactor+Gallium
anomalies in a short (~5yr) timescale; excellent bang for buck!• ANR request (CEA, LAPP, LPSC): 800 k€ + 2 postdocs• LAPP’s rôle : Radioactive source calibration system. Possibility
of mechanics of shielding.Engineering manpower seems available for the requested period
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