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Double-CH  13  13 Z: A search for  13

Double-CH  13  13 Z: A search for  13. Thierry Lasserre (CEA/Saclay) On behalf the Double-Chooz collaboration NuFact04, Osaka, Japan July 28 th 2004. Letter of Intent. CHOOZ site & Detector Overview. Double-Chooz, Ardennes, France. Chooz-Near. Chooz-Far.

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Double-CH  13  13 Z: A search for  13

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  1. Double-CH1313Z:A search for 13 Thierry Lasserre (CEA/Saclay) On behalf the Double-Chooz collaboration NuFact04, Osaka, Japan July 28th 2004

  2. Letter of Intent T. L. (Saclay) - NuFact04 -

  3. CHOOZ site & Detector Overview T. L. (Saclay) - NuFact04 -

  4. Double-Chooz, Ardennes, France Chooz-Near Chooz-Far Near site: D~100-200 m, overburden 50-80 mwe Far site: D~1.1 km, overburden 300 mwe T. L. (Saclay) - NuFact04 -

  5. The CHOOZ-far site September 2003 T. L. (Saclay) - NuFact04 -

  6. The CHOOZ-far detector Shielding: 0,15m steel 7 m  target: 80% dodecane + 20% PXE + 0.1% Gd (acrylic, r=1,2m, h = 2,8m, 12,7 m3) -catcher: 80% dodecane + 20% PXE (acrylic, r+0,6m – V= 28,1 m3) 7 m Non scintillating buffer: scintillator+quencher (r+0.95m, , V=100 m3) 7 m PMT supporting structure Muon VETO: scintillating oil (r+0.6 m – V=110 m3) CHOOZ existing pit T. L. (Saclay) - NuFact04 -

  7. Full detector simulation ~500 PMTs/detector T. L. (Saclay) - NuFact04 -

  8. 250 m 125 m The CHOOZ-near site Near detector @100-200 m from the cores Exact position under study, in collaboration with EDF T. L. (Saclay) - NuFact04 -

  9. @DAPNIA The CHOOZ-near laboratory • 60 m.w.e. overburden • 12 m compacted earth • 3 meter high density material 15m 5m ~10m T. L. (Saclay) - NuFact04 -

  10. How to improve Chooz:statistics & systematics T. L. (Saclay) - NuFact04 -

  11. Improving CHOOZ– Statistical error - @CHOOZ: R = 1.01  2.8%(stat)2.7%(syst) • Luminosity increase L = t x P(GW) x Vtarget T. L. (Saclay) - NuFact04 -

  12. Improving CHOOZ– Systematical error - @CHOOZ : σsys=2.7% • Decreasing systematical error • Improve the detector concept • Two identical detectors  towards σrelative~0,6% • Backgrounds – improve S/B>100  error<1% T. L. (Saclay) - NuFact04 -

  13. Reactor induced systematics 2 detectors  cancellation of the reactor physical uncertainties T. L. (Saclay) - NuFact04 -

  14. Relative Normalisation: Detector • Solid angle - Distance measured @10cm + Monitoring of the  source barycenter… • Target volume - @CHOOZ : 0.3% [simple measurement] - Goal ~0.2% [same apparatus for both detectors] - Not trivial … • Density - 0.1% achievable, but accurate temperature control mandatory • H/C ratio & Gd concentration - Absolute measurement is difficult : 1% error @CHOOZ - Plan: use the same batch to fill both detectors • Boundary effect at the inner vessel interface (spill in/out) - Neutron transport slightly different due to solid angle effect - MC study to be done to check that it is negligible • Live time to be measured accurately by several methods T. L. (Saclay) - NuFact04 -

  15. Detector induced systematics M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374 A single scintillator batch will be prepared to fill both detectors with the same apparatus T. L. (Saclay) - NuFact04 -

  16. e+ Relative Normalisation: Analysis • @CHOOZ: 1.5% systematic error - 7 analysis cuts - Efficiency ~70% Sélection cuts - positron energy [energy threshold] • - e+ position/géode (30cm) [position reconstruction] • - neutron energy [energy cut - calibration] • - n pos./géode (30 cm) [position reconstruction] • - distance e+ - n [position reconstruction] • - t e+ - n [neutron capture on Gd] • - n multiplicity [level of accidental bkg] • Goal Double-CHOOZ: <0.5% systematic error - 2 to 3 analysis cut Sélection cuts • - neutron energy • (- distance e+ - n ) [level of accidentals] • - t e+ - n e+ n t T. L. (Saclay) - NuFact04 -

  17. Systematics uncertainties T. L. (Saclay) - NuFact04 -

  18. Backgrounds T. L. (Saclay) - NuFact04 -

  19. Backgrounds Estimates • CHOOZ: N/S ~ 4% • Double-CHOOZ-Far (300 mwe): 12.7 tons  Signal x 3 • Modification of the detector design  + expensive • Uncorrelated: N/S(chooz) ~ 4% : Double-Chooz: Sx3 & N/3  < 0.5% • Correlated events: N/S < 1% • CHOOZ : ~<1 recoil proton per day • Double-CHOOZ: liquid active buffer +30cm  ~0.3 events per day • - Double-CHOOZ-near (50 mwe): Signal x 50-100 S(CHOOZ-Far) • -Key advantage: Dnear ~ 100-200m  Signal x 50-100 ! • -Uncorrelated: CHOOZ-Far backgrounds x 50  N/S < 1% • -Correlated events: CHOOZ-Far x <30  N/S < 1% • (but not a comprehensive list of backgrounds …) T. L. (Saclay) - NuFact04 -

  20. Neutron Induced Background • Cosmic muons create fast neutrons through spallation and muon capture in the rock surrounding the detector • Fast neutron slowns down by scattering into the scintillator; it could deposit between 1-8 MeV and be later captured on Gd ! • Full simulation – Geant + Fluka • Old Chooz simulation: 300 m.w.e. 31hours – MC is reliable ! • Simulated: Nb<1.6 evts/day (90% C.L.) • Measured in-situ: Nb=1.1 evts/day • Double-Chooz simulation: • 338 106 tracked – 580 103 neutrons tracked • 1 neutron created a muon event • Far detector: Nb<0.5 evt/day (90% C.L.) • Near detector: Nb<3.2 evts/day (90%C.L.)  Surrounded by 100 mwe rock shielding T. L. (Saclay) - NuFact04 -

  21. Overview of Scintillator developement & Acrylic vessel design T. L. (Saclay) - NuFact04 -

  22. R-COO- 3+Gd 3+Gd R-COO- (R-COOH)x -OOC-R Gd-Acac Gd doped scintillator development • Goal: 0.1% Gd loaded scintillator (follow up of LENS R&D) • Light yield ~8000 /MeV + attenuation length > 5m • STABLE & Compatible with acrylic • Ongoing: 1/ Long term stability  2004 2/ scintillator-acrylic compatibility • ~80 days Ageing test @40-50o [x2-4 each 100] • Material compatibility test + acrylic design Carboxylate T. L. (Saclay) - NuFact04 -

  23. Scintillator liquid baseline Vtot = 250 m3 (200 tons) • Reference recipe • PC (C9H12), PXE (C16H18) attack acrylics • Dodécane + PXE more resistant … • R&D Saclay+MPIK+Gran Sasso (08/2004) • Fluors 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 m T. L. (Saclay) - NuFact04 -

  24. Acrylic vessels Target Target Gamma catcher Final assembly on Chooz’s site Assembly at the manufacturer 3.6m 2.4m 4m 2.8m 2m Gamma catcher • Empty weight: • Target = 220kg • Gamma catcher = 470kg  Maximum stress: 12 MPa Thickness: 6 mm T. L. (Saclay) - NuFact04 -

  25. Sensitivity &Discovery Potential T. L. (Saclay) - NuFact04 -

  26. Spectrum deformation @Double-CHOOZ sin2(213)=0.15 T. L. (Saclay) - NuFact04 -

  27. 90% C.L. sensitivity if sin2(213)=0 m2=2.4 10-3 eV2 3 years (efficiency included) sin2(213)<0.024 T. L. (Saclay) - NuFact04 -

  28. P. Huber et. al. hep/0403068 Attempt to compare Double-Chooz with Beams & Superbrams m2=2.0 10-3 eV2 Double-CHOOZ starts with two detectors in January 2008 T2K starts at FULL intensity in January 2010 T. L. (Saclay) - NuFact04 - Th. Lasserre

  29. sin22θ13 = 0.08 sin22θ13 = 0.14 sin22θ13 = 0.04 Attempt to compare Double-Chooz with T2K (3σ discovery potential) T. L. (Saclay) - NuFact04 -

  30. Mini-Inca 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 ! • Cost issue … 10,000$/day/inspector … • 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” • Double-CHOOZ-IAEA: CEA/Saclay + Subatech Nantes + Kurchatov • Perform new antineutrino spectrum @ILL reactor (Mini-Inca + -spectrometer) • Use Double-Chooz near as a ‘prototype’ for nuclear reactor monitoring • Other studies like large and very large underwater antineutrino detectors … T. L. (Saclay) - NuFact04 -

  31. Summary & outlook • Strong Support for the EDF power company & local authorities to perform a 2nd experiment at Chooz (castle available again for physicists !!!) Double-CHOOZ sensitivity: sin2(213)<0.025-0.03, 90% C.L. (m2 = 2.0-2.5 10-3 eV2) Current limit: CHOOZ : sin2(213)<0.2  discovery potential ! • Technology / design well known (CHOOZ, BOREXINO, KamLAND, …)  few R&D needed : Gd loading (stability) + material compatibility (Started, to be completed in half a year) • Collaboration: Saclay, APC, Subatech, TUM, MPIK, Tubingen Univ. Hamburg Univ., Kurchatov, Univ. Alabama, Univ. Tennessee, Univ. Lousiana, Univ. Drexel, Argonne, + Italian groups soon …  (maxi-)letter of intent (May 2004)  final proposal end of 2004 • Approved in France. Detector cost ~7 Million euros (Civil engineering cost not included) • Our Goal @Double- CHOOZ: Construction starts end of 2005 Start data taking in 2007 (far) & 2008 (near + far) Far detector starts Near detector starts 2004 2005 2006 2007 2008 2009 2003 in 2011 sin2(213) < 0.025 Site Prop. design Construction ? Data taking T. L. (Saclay) - NuFact04 - in 2009: sin2(213) < 0.05

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