1 / 42

Chasing  13 with new experiments at nuclear reactors

Chasing  13 with new experiments at nuclear reactors. Thierry Lasserre Saclay NuFact04, Osaka July 26 2004. solar  + KamLAND + reactor  ?. atmospheric  + K2K + MINOS – Superbeams …. superbeam  + reactor . sin 2 (2  13 )<0.20 (CHOOZ)   13 ? (small angle)

benard
Download Presentation

Chasing  13 with new experiments at nuclear reactors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chasing 13with new experiments at nuclear reactors Thierry Lasserre Saclay NuFact04, Osaka July 26 2004

  2. solar  + KamLAND + reactor  ? atmospheric  + K2K + MINOS – Superbeams … superbeam  + reactor  sin2(213)<0.20 (CHOOZ)  13 ? (small angle) Hierarchy  sign(m232 ) ? CP violation   phase ? MSW-LMA m212~O(10-4/-5) eV2 sin2(212)~0.8 (large angle) m232~2-3 10-3 eV2 sin2(223)~1 (maximal angle) The neutrino sector [m221- 12]– [m232 - 23]– sign(m232) - 13-  But no absolute mass scale coming from oscillation experiments -->  & 0 decays ? T.L. (Saclay) - NuFact04 -

  3. Measurement at reactors& complementarity with LBL T.L. (Saclay) - NuFact04 -

  4. e  x Best current constraint: CHOOZ e disappearance experiment Pth= 8.5 GWth, L = 1,1 km, M = 5t (300 mwe) R = 1.01  2.8%(stat)2.7%(syst) World best constraint ! @m2atm=2 10-3 eV2 sin2(2θ13)<0.2 (90% C.L) M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374 T.L. (Saclay) - NuFact04 -

  5. 13& reactor experiments • <E> ~ a few MeV  only disappearance experiments  sin2(213) measurement independent of -CP • 1-P(e e) = sin2(213)sin2(m231L/4E) + O(m221/m231) •  weak dependence in m221 • a few MeV e + short baselines  negligible matter effects (O[10-4] )  sin2(213) measurement independent of sign(m213) 13 & beam experiments LBL  disappearance : sin2(223)  2 solutions : 23 & /2-23 |m213|  2 solutions m1>m3 or m3>m1 Appearance probability : sin2(2 13 ) reactor P(e) ~ K1 sin2(23 ) sin2(213 ) + K2 sin(223 ) sin(13 ) sign(m231) cos()  K3 sin(223 ) sin(13 ) sin ()  beam • K1,K2,K3: constants known with experimental errors) • dependence in sin(223), sin(23)  2 solutions • dependence in sign(m231)  2 solutions • -CP phase  [0,2]  interval of solutions P(e) T.L. (Saclay) - NuFact04 -

  6. 0.07 0.05 P( e) 0.03 sin  correlation T2K measurement 0.01 0.14 0.1 0.06 0 sin2(213) CP- phase induced ambiguity T.L. (Saclay) - NuFact04 -

  7. 0.07 0.05 P( e) T2K measurement 0.03 0.01 reactor measurement 0.14 0.1 0.06 0 sin2(213) 23 induced ambiguity LBL + reactor combination might help to solve the 23 degeneracy T.L. (Saclay) - NuFact04 -

  8. Improving CHOOZ is difficult ! T.L. (Saclay) - NuFact04 -

  9. Near detector Far detector 50 years of reactor neutrino experiments … 1956  Discovery of neutrinos @Savannah River - First detection of reactor neutrinos 1990’s  Reactor neutrino flux measurements 1995  Nobel Prize to Fred Reines 2002 Discovery of massive neutrinos and oscillations confirmed by KamLAND From discovery to metrology ! G. Mention (APC) T.L. (Saclay) - NuFact04 -

  10. e e,, One nuclear plant & two detectors D1 = 0.1-1 km D2 = 1-3 km Nuclear reactor 1,2 core(s)  ON/OFF : ok  4 cores  ON/OFF : no ! Near detector 5-50 tons > 50 mwe Far detector 5-50 tons > 300 mwe • Isotropic e flux (uranium & plutonium fission fragments) • Detection tag : e + p  e+ + n, <E>~ 4 MeV, Threshold ~1.8 MeV • Disappearance experiment: suppression+shape distortion between the 2 detectors • 2 IDENTICAL detectors (CHOOZ, BOREXINO/CTF type, KamLAND) • Minimise the uncertainties on reactor flux & spectrum (2 % in CHOOZ) • Cancel cross section uncertainties • Challenge: relative normalisation between the two detectors < 1% ! T.L. (Saclay) - NuFact04 -

  11. Improving CHOOZ is difficult … @CHOOZ: R = 1.01  2.8%(stat)2.7%(syst) • Statistics • Increase luminosity L = t x P(GWth) x Np(target) • Increase fiducial volume & exposure • ~2700 events in CHOOZ but >40,000 for the next experiment  σ < 0.5% • Experimental error • 2 detectors cancel neutrino flux and cross section systematic uncertainty [~2%] • Identical detectors  decrease detector systematic uncertainties [<1%] • Movable VS non movable detectors : cross calibration, but error might be increased ? • Backgrounds (S/N~25 in CHOOZ ; Goal S/N >100 in the new experiment) • Uncorrelated background (measurement in-situ) – Correlatedbackgrounds ( induced) • Underground site required: >300 m.w.e for the far site to improve CHOOZ • S/N equivalent for Near and Far detector (near detector could be shallower) • Reactor ON/OFF measurement  1, 2, 4, or up to 7 reactor cores ? T.L. (Saclay) - NuFact04 -

  12. Anti-e tag: e + p  e+ + n, Q~1.8 MeV Threshold • Prompt e+, EP=1-8 MeV, visible energy • Delayed neutron capture on Gd, ED=8 MeV • Prompt(/) - Delayed(/) pulse shape discrimination Time correlation:   30sec Space correlation: < 1m3 Reactor antineutrino detection delayed event: prompt event: Or Gd capture (8 MeV) T.L. (Saclay) - NuFact04 -

  13. Gd  = 100 % n Gd e+ e+ n n Interaction  e+ e+ n H  = 0 % H Why two identical detectors … Fiducial volume Acrylic vessel Gd ~0.1% scintillator unloaded spill in/out effect  signal No  signal A ~1% irreducible systematic error from the spill in/out effect Boundary effect  2 identical inner vessels Scintillator doped with 0.1% Gd MUST be perfectly stable over the life time of the experiment (>5 years) T.L. (Saclay) - NuFact04 -

  14. Observable: e+ spectrum (Double-CHOOZ configuration) m2atm = 2.0 10-3 eV2 sin2(213)=0.04 sin2(213)=0.1 sin2(213)=0.2 sin2(213)=0.04 sin2(213)=0.1 sin2(213)=0.2 Events/200 KeV/3 years E (MeV) E (MeV) Near Detector: ~ 1.8 106 events -Reactor efficiency: 80% -Detector efficiency: 80% -Dead time: 50% Far Detector: ~ 34 000events -Reactor efficiency: 80% -Detector efficiency: 80% T.L. (Saclay) - NuFact04 -

  15. Far/Near energy bin ratio @1,05 km Example of e oscillation at reactor(Double-CHOOZ configuration ) Rate + shape information if 13 not too small Note: optimum baseline ~1.5km T.L. (Saclay) - NuFact04 -

  16. X 2 Double CHOOZ & KASKA (10 tons) Detector size scale Reactor/13 Example ~20 t CHOOZ 5 t Borexino 300 t KamLAND 1000 t Angra, Daya-Bay, Braidwood T.L. (Saclay) - NuFact04 -

  17. 90% C.L. sensitivity if sin2(213)=0 @m2=2.0 10-3 eV2 σbkg σbkg σbkg T2K 1% Huber, Lindner, Schwetz & Winter: hep-ph/0303232 G. Men tion & T. L. 0.1% reactor 1 (2 RNU) reactor 2 (40 RNU) RNU = Reactor Neutrino Unit : 1 RNU = 1031 free H GWth year • Reactor1 (0.5 km, 2.3 km): ~13 tonsPXE x 10 GW x 3 years  sin2(213)<~0.02, 90% C.L • Reactor2 (0.5 km, 2.3 km): ~270 tonsPXE x 10 GW x 3 years  sin2(213)<~0.01, 90% C.L T.L. (Saclay) - NuFact04 -

  18. sin2(213) at LBL & reactors @m2=2.0 10-3 eV2 (3 ktons ?) Double-CH1313Z CHOOZ alone 90% C.L Huber, Lindner, Schwetz & Winter (‘extremum’ of projection of the 2 manifold on the sin2(213) axis) T.L. (Saclay) - NuFact04 -

  19. Current proposal for new reactor experiments … T.L. (Saclay) - NuFact04 -

  20. Nuclear reactors in the world T.L. (Saclay) - NuFact04 -

  21. World momentum • December 2002: First European meeting, MPIK Heidelberg • April 2003: Second European meeting, PCC, Paris • May 2003: First international workshop, University of Alabama, US • October 2003: Second international workshop, TUM, Germany • March 2004: Third international workshop, Niigata, Japan • Next workshop in Brazil, January 2005 125 authors, 40 Institutions White Paper Report on Using Nuclear Reactors to search for a value of theta 13 hep-ex/0402041 T.L. (Saclay) - NuFact04 -

  22. Which site for the experiment ? Penly Chooz Cruas Braidwood Daya bay Krasnoyarsk Kashiwasaki Diablo Canyon Taiwan Angra One reactor complex Two underground cavities @0.1-1 km & ~1-2 km T.L. (Saclay) - NuFact04 -

  23. The Krasnoyarsk site: Kr2Det Russian Research Center “KurchatovInstitute” Single reactor core • P=1.6 GWth • ON/OFF cycle [50 days ON & 7 days OFF] No civil construction >50 tons detectors • Near: >50 tons – 115 m – 600 mwe • Far: >50 tons - 1.1 km - 600 mwe Sensitivity • 0.5% systematic error • sin2(213) < 0.015 (m2 =2.5 10-3 eV2, 90% C.L.) Prospects • Visit in summer 2003 cancelled by Russian authorities • Site not available for “political” reasons Completely underground facility was used by the Soviets for weapons production. T.L. (Saclay) - NuFact04 -

  24. 1st generation: sin2(213)~0.01-0.03 2nd generation: sin2(213)~0.01 + shape only analysis Current proposals Double-Chooz Braidwood Daya bay Kaska Angra T.L. (Saclay) - NuFact04 -

  25. Braidwood (Illinois) Two reactor cores • P=2 x 3.6 GWth Civil construction • Flat topology • Near & Far: 120m shafts (10m diameter) • + laboratories (25-35 M$) Two 50 tons detectors • Near: 25-50 tons – 300 m – 450 mwe • Far: 25-50 tons – 1.5-1.8 km - 450 mwe • Movable detector (move on the surface, lift with crane) 3 years Sensitivity • 0.5% systematic error • No signal: sin2(213) < 0.01 (90% C.L.) Prospects (not yet approved) • Construction in 39 month - running in 2009. Cost ~45 M$ • Geological studies ongoing T.L. (Saclay) - NuFact04 -

  26. Braidwood (Illinois) ANL, Chicago, Columbia, FNAL, Kansas, Oxford, Pittsburgh, Texas Civil construction Detector sketch T.L. (Saclay) - NuFact04 -

  27. Daya Bay Four reactor cores • P=4 x 2.9 = 1.6 GWth • + two new cores for 6 GWth in 2011 Civil construction • Near: 1 km tunnel + laboratory • Far: 2 km tunnel + laboratory ~10 tons detector modules • Near: 25 tons - 300 m – 200 mwe • Far: 50 tons - 1.5-1.8 km - 700 mwe • Movable detector concept Sensitivity • 0.4% systematic error • sin2(213) < ~ 0.01 (90% C.L.) ? Prospects (not yet approved) • 2004-05: R&D, 2006-07: Construction • 1 Near detector running in 2008 • Geological & safety studies ongoing T.L. (Saclay) - NuFact04 -

  28. Daya Bay IHEP, CIAE, Tsinghua Univ., Hong Kong Univ., Hong Kong Chinese Univ, (Berkeley, Caltech) R&D Near detector: 2 x 10 tons modules Far detector: 4 x 10 tons modules 3 years of data taking sin2(213) < ~ 0.01-0.02 (90% C.L.) T.L. (Saclay) - NuFact04 -

  29. Kaska (Kashiwasaki, Japan) Seven reactor cores • P=24.3 GWth • 2 near detector mandatory Civil construction • 2 Near: ~70 m 6m shafts + laboratories • Far: ~250 m 6m shaft + laboratory Multiple detectors • 2 Near: 8 tons – 300-400 m – 100 mwe • Far: 8 tons - 1.3-1.8 km - 500 mwe Sensitivity • 0.5% systematic error • sin2(213) < 0.025 (90% C.L.) Prospects (not yet approved) • 2004-05: R&D, 2006-07: Construction. Running in 2008. Cost ~20 M$ • Geological studies ongoing – Prototype to be built for R&D. T.L. (Saclay) - NuFact04 -

  30. KASKA (Japan) Tohoku Univ., Niigata Univ., Rikkyo Univ., KEK, Kobe Univ. Tokyo Institute of Technology, Tokyo Metropolitan Univ. Sensitivity (3 years): sin2(213)<0.026 @90% C.L T.L. (Saclay) - NuFact04 -

  31. Double-Chooz (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 -

  32. Double-Chooz features Twin reactor cores • N4 type P=2x4.2 GWth Civil construction • Near: 20x10x5m experimental hall • Artificial overburden Two 10 tons detectors • Near: 100-200 m – 60-80 mwe • Far: 1.05 km - 300 mwe 3 years Sensitivity • 0.6% systematics • No signal: sin2(213) < 0.02-03 (90% C.L.) • Signal: sin2(213) > 0.04-05 (3σ) Prospect (approved & funded in France) • 2007: far detector running • 2008: near detector running • Cost ~7Meuros + civil constr. @DAPNIA Near detector site (to be built) Existing Far detector site T.L. (Saclay) - NuFact04 -

  33. 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) @DAPNIA CHOOZ existing pit T.L. (Saclay) - NuFact04 -

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

  35. 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 -

  36. 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 background] • 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 T.L. (Saclay) - NuFact04 -

  37. sin22θ13 = 0.08 sin22θ13 = 0.14 90% C.L. 3σ C.L. Sin2(2θ13) = 0.04 Attempt to compare Double-Chooz with T2K (3σ discovery potential) Double-CHOOZ starts with two detectors in January 2008 T2K starts at FULL intensity in January 2010 Assumption From Huber, Lindner, Schwetz (hep/0405032) T.L. (Saclay) - NuFact04 -

  38. Letter of Intent + Univ. Alabama - Univ. Louisiana - Univ. Tennessee - Univ. Drexel – Argonne T.L. (Saclay) - NuFact04 - Th. Lasserre

  39. 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 • 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 -

  40. Towards evidence of non vanishing  • T2K: 10 years running (0.75MW beam & Super-Kamiokande) • Reactor (second generation): 103 104 GWth.ton.year Reactor [103 GW.t.y] @ ~1km 200 tons 10 GWth 5 years H. Minakata & H. Sugiyama, hep-ph/0309323 Regions consistent with the hypothesis =0 (90% CL) By the reactor-LBL combined measurement T.L. (Saclay) - NuFact04 -

  41. 2nd generation project: Angra (Brazil) Argonne + Brazil : CBPF, UNICAMP, USP, PUC-RIO Single reactor core • P=4.1 GWth • A new core is being built (2006) Civil construction • Near: 6x6x60m tunnel + 10x10x12m exp. hall • Far: 6x6x450m tunnel + 10x10x12m exp. hall • + emergency shafts Two >100 tons detector • Near: 300 m – 50 mwe ? • Far: 1.35 km - 600 mwe • Non movable detectors concept Sensitivity • 5 years  >103 GWth.t.y • sin2(213) < 0.01 (90% C.L.) • 1% systematic error • Shape only analysis T.L. (Saclay) - NuFact04 -

  42. Conclusion & outlook • A new reactor neutrino experiment could provide an evidence of the oscillation in the (1,3) sector in 2009 • Reactor & LBL programs provide independent and complementary measurements of 13. But current proposals have low synergy … Of course reactor experiments won’t replace the rich LBL program. However, a preliminary value of 13 might help to design the best CP- detector: • Several projects of reactor experiment & strong world momentum • First generation :sensitivity sin2(213)~0.02-0.03 - Rate + Shape • Motionless detectors: Double-Chooz (funded in France), KASKA • Movabledetectors: Daya-bay, Braidwood • Second generation : sensitivity sin2(213)<0.01 - Shape only (>103 GWth.tons.years): • Motionless detectors: Angra T.L. (Saclay) - NuFact04 -

More Related