Contents. General introduction to reactor θ 13 measurements Status review of ongoing 3 projects (in order of expected far-site data taking start)

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3 Contents General introduction to reactor θ 13 measurements Status review of ongoing 3 projects (in order of expected far-site data taking start) Double Chooz (France) RENO (Korea) Daya Bay (China) Summary Material thanks to: S.B. Kim (RENO) L. Wen (Daya Bay) pls. see also poster submitted to NNN10 3

4 Why reactors? ~6 ν s/fission, ~200MeV/fission ν/sec for a typical commercial reactor (1GW power ~ 3GW thermal) Reactors are powerful and free sources of low-energy (isotropic) neutrinos ν ν E ν ~ a few MeV ν ν ν ν Always full power (example) Can t switch off easily 4

5 Oscillation maximum: 1.27Δm 2 (ev 2 )L(km)/E(GeV)=(2n+1)π/2 For Δm 2 32(31) ~ ev 2 and E ~ 1 GeV, L ~ O(400km): accelerator long-baseline exp t (T2K,...) For Δm 2 32(31) ~ ev 2 and E ~ 4 MeV, L ~ O(1.6km): reactor mid-baseline exp t (DC,...) For Δm 2 21 ~ ev 2 and E ~ 4 MeV, L ~ O(50km): reactor long-baseline exp t (KamLAND) 5

6 Reactor ν: direct to θ 13 measurement Disappearance at (1-3) osc. maximum (L=1~2km) P ( ν e ν e )=1 sin 2 2θ 13 sin 2 m2 31L 4E +O(10-3 ) from Δm 2 21 oscillation (1-3) (1-2) ~ sin 2 2θ 13 Measure this small deficit. Thanks to Δm 2 21 <<Δm 2 32(31), it is a pure θ 13 measurement. KamLAND 1~2km for 4MeV ν e 6

7 Complementarity to accelerator-θ 13 appearance exp t sinδ ambiguity L=300km Measuring with both methods is important! 7

8 Detection principle Inverse-beta decay (E thresh =1.8MeV) ν e + p n + e + e + + e 2γ E ν 0.8MeV ( ) n + Gd Gd' +γs ( ) E = 8MeV cf. KamLAND has no Gd n+p d+γ(2.2mev) Delayed coincidence drastically reduces the background. 8

9 The energy spectrum peaks at 3.5~4 MeV Gratta/ ν2004 9

10 Previous best-limit exp.: CHOOZ P=8.4GW th σ sys. =2.8%, σ stat. =2.7% L=1km D=300mwe M=5ton sin 2 2θ 13 Δm 2 = ev 2 10

11 How to do better than CHOOZ? All 3 ongoing projects have similar strategies. 2-site concept: measure un-oscillated ν flux at the near detector(s) and take a ratio at the far detector. Cancels most of source, cross-sec, target-related systematics. Building identical detectors is critical for precise measurement. 4-layer vessels: Target-γCatcher-Buffer-µVeto. Gd-doped Target defines the hardware-defined fiducial volume. γ-catcher reconstructs energy of γ s escaping from Target. non-scintillating Buffer oil reduces γ backgrounds from PMTs, etc. in addition to µ-veto, also non-liquid Outer Veto for µ tagging. Better precision: <0.5% σstat and <0.5% σsyst. Larger target volume (CHOOZ: 5 tons) Longer run (CHOOZ Gd-doped LS degraded: new developments) Controlling systematics is the key. Aiming sin 2 2θ13 <

12 Backgrounds ν signature: ~1-8 MeV prompt + ~8 MeV delayed, in coincidence within O(100) µs. Accidental: from γ s (PMT etc.) and cosmic-induced n s. Depends on radio-purity and overburden (~2% in DC far). Can be precisely measured (time shifting, etc.). Correlated: cosmic induced. Spallation fast n: recoil-proton prompt, n delayed. ~0.2% in DC far. Expected prompt energy spectrum ~ flat. Cosmogenic isotopes: e.g. 9 Li β(prompt)-n(delay) decays. ~1.4% in DC far. Long-lived: impossible to veto after µ. Estimate b.g. with analysis. Timing and position correlations. 12

13 One possible case of Complementarity to Accelerator-θ 13 L=300km If.. ±0.025(DC) ±0.004 Degeneracy Solved! θ 23 <π/4 13

14 Double Chooz 14

Site of Double Chooz ν flux Normalisation @400m 2 identical targets of 8.3t ν oscillation @1050m PHASE 1 (2011-12) - far detector only - sin 2 (2θ 13 )<0.

15 Site of Double Chooz ν flux 2 identical targets of 8.3t ν PHASE 1 ( ) - far detector only - sin 2 (2θ 13 )<0.06 (1,5 years, 90% C.L.) PHASE 2 ( ) - far + near - sin 2 (2θ 13 )<0.03 (3 years, 90% C.L.) 2 reactors-n4 2x4.27 GW th ν e /s NuFact10 M. Dracos IPHC/CNRS-UdS 13

16 Detector design!"#$%&'$#()&*+,-#./&-/.0#.++,#(%&-#%.*- 12.$+3.04)&56&/7&(8&-#$,+ 900$%&'$#() :;&7 < DE;F&GHIJ&K;&F&C$#%,3$/,0$J&AA!J&I.-LB1IM I"88$%) 55;&7 < &(8&0(0&-/.0#.++,#.04&7.0$%,+&(.+& >&<:;&ABC- D<;F&C$#%,3$/,0$J&?;F&!.+M N,77,&/,#/2$%) OOP<&7 < &(8&+.=".3&-/.0#.++,#(% DEKF&Q(3$/,0$J&6;F&!.+J&EF&ARSJ&AA!J&I.-LB1IM T$"#%.0(&#,%4$#) 5;P<&7 < &(8&+.=".3&-/.0#.++,#(%&3(*$3&U.#2& ;P5&4VG&(8&N3 u BONGRAND (LAL) Double Cho

17 PMT developments and evaluations Measurement box in Tokyo QExCE mapping HPK R7081 high performance low background 10" PMT 32PMT test stand in MPI Heidelberg 17

18 18 engineer s view Our MC s (G4)view our favorite view A. Cabrera, ν 2010 Anatael Cabrera (CNRS-IN2P3 & APC)

19 Where do we stand today? Filling! 4 liquids at the same time: delicate operation. Finished filling yesterday (13/Dec/ :59am)! All electronics, trigger, R/O for Inner Det. and Inner Veto installed, DAQ is being commissioned as we filled. Top shield not yet installed: detector irradiated by environmental γ s. Detector is yet uncalibrated. Most of calibration systems next year (only embedded LED-Light Injection systems installed). Outer Veto installation next year. 19

20 Filling... A level measurement device Filling station 20

21 Light from wet detector Normalised Entries PRELIMINARY Uncalibrated Double Chooz M. Kuze, NNN10 Toyama Time(ns) Average time response of light from a run during liquid filling. Caveats: scintillator partially filled. uncalibrated detector missing top shield: lots of rock gamma s Once the above are done (hopefully Jan. 2011), start detector tuning towards neutrino data-taking (trigger threshold, etc.). 21

22 Chooz limit = 0.15 Sensitivity in time Far Detector only Far+Near Detectors

23 RENO 23

24 Google Satellite View of Experimental Site YongGwang NPP Total ~16.4 GWth 1380m 290m Target 16 tons Sensitivity: sin 2 2θ13<0.02

25 RENO Experimental Setup

26 RENO Detector (Gd loaded liquid scintilllation detector)

27 PMT assembling & barrel PMTs

28 Schedule Activities Detector Design & Specification Geological Survey & Tunnel Design Detector Construction Excavation & Underground Facility Construction Detector Commissioning & Data Taking Tunnel facility, detector structure & buffer steel tanks completed June 2010 : Acrylic containers installed Aug : PMT test completed Aug. ~ Dec : Installation of PMTs, veto tyvek and liquid handling system Dec ~ Jan : Installation of DAQ & HV and detector closing Jan. ~ Mar : Filling with liquid scintillator and detector commissioning Mar : Start data taking

29 Daya Bay 29

30 Far: 80 ton 1600m to LA, 1900m to DYB Overburden: 350m Muon rate: 0.04Hz/m 2 Daya Bay Layout LA: 40 ton Baseline: 500m Overburden: 112m Muon rate: 0.73Hz/m 2 DYB: 40 ton Baseline: 360m Overburden: 98m Muon rate: 1.2Hz/m 2 Shenzhen Hong Kong 55km 30

Daya Bay Detectors Redundancy is a unique feature for this

31 Daya Bay Detectors Redundancy is a unique feature for this experiment: Iden[cal an[neutrino detector modules to reduce errors and cross check. Mul[ple muon veto: Two zones of Cerenkov detector + RPC at the top. Total efficiency > (99.5 ± 0.25) %. Top reflector calibration system PMT Inner acrylic vessel (3m φxh) Outer acrylic vessel (4m φxh) Stainless steel vessel BoRom reflector 5m Mineral Oil LS Gd- LS 5m 31

32 Detectors Assembly move SSV SSV sits in pit clean SSV inside insert bottom reflector insert Inner AV insert outer AV close outer AV lid test Gd-LS filling probe lift PMT ladder install top reflector close SSV lid install ACUs 32

to filling them with liquid scin[llator.

33 Light from LEDs can be observed as well as Cherenkov light caused by cosmic ray muons passing acrylic. ACU Dry Run of the first AD pair A full end- to- end test of the fully instrumented An[neutrino Detectors prior to filling them with liquid scin[llator. PMT Charge (PE) with LED flashing LED Flashing Double pulse LED to mimic events LED Consistent performance of AD pair calibra[on LED Off- axis LED Muon 33

Occupancy Daya Bay Hall: data taking, Fall 2011 Ling Ao

34 Tenta[ve Schedule October 2010, first AD pair complete, Dry- Run tests finished October 2010, Daya Bay Near Hall Occupancy Daya Bay Hall: data taking, Fall 2011 Ling Ao and Far Halls: data taking, Fall Reach the goal! 34

35 Conclusion Timely reactor medium-baseline experiments would be complementary to acc.-based experiments, leading to much richer physics outcome with their synergy. Systematics is the key issue for disappearance exp t. Double Chooz: Far det. is full! Near+Far: by the end of RENO: Filling from Jan Daya Bay: Near: fall 2011, Near+Far: fall 2012 Experimental context w.r.t. ν beam LBL experiments Stay tuned for news!! Year sin 2 2Θ 13 sensitivity reach GLoBES 2009 sin 2 2Θ 13 sensitivity limit NH, 90% CL CHOOZ Solar excluded 35 Double Chooz T2K RENO Daya Bay NO A: Ν Ν NO A: Ν only

36 backup 36

Tübingen MPIK Heidelberg TU München U. Aachen U. Hamburg Tohoku U. Tokyo Inst. Tech. Tokyo Metro. U. Niigata U. Kobe U. Tohoku Gakuin U.

37 Double Chooz collabora.on Brazil France Germany Japan Russia Spain UK USA CBPF UNICAMP UFABC APC CEA/DSM/IRFU: SPP SPhN SEDI SIS SENAC CNRS/IN2P3: Subatech IPHC ULB EKU Tübingen MPIK Heidelberg TU München U. Aachen U. Hamburg Tohoku U. Tokyo Inst. Tech. Tokyo Metro. U. Niigata U. Kobe U. Tohoku Gakuin U. Hiroshima Inst Tech. INR RAS IPC RAS RRC Kurchatov CIEMAT-Madrid Sussex U. Alabama ANL U. Chicago Columbia U. UCDavis Drexel U. IIT KSU LLNL MIT U. Notre Dame Sandia National Laboratories U. Tennessee Spokesperson: H. de Kerret (IN2P3) Project Manager: Ch. Veyssière (CEA-Saclay) Web Site:

38 RENO collaboration (13 institutions and 40 physicists) Chonnam National University Chonbuk National University Dongshin University Gyeongsang National University Kyungpook National University Pusan National University Sejong University Seokang Information University Seokyeong University Seoul National University Sungkyunkwan University Institute of Nuclear Research RAS (Russia) Institute of Physical Chemistry and Electrochemistry RAS (Russia) +++

39 Construction status

40 Installation of Acrylic Vessels by KOA Tech. Korea

41 Installation of 1 st PMT ( ) & bottom PMTs

42 Installation of VETO tyvek & outer PMTs

43 Summary θ θ

44 RENO Experimental Setup Experiments Location Thermal Power (GW) Distances Near/Far (m) Depth Near/Far (mwe) Target Mass (tons) Cost (US $) # of people Double- CHOOZ France / /300 10/10? > 160 RENO Korea / /450 16/16 ~10M 40 Daya Bay China (500)/1985(1613) 260/ /80? > 230

45 !"# $%&% '%& ()**%+),%-.)/ Europe (3) (9) JINR, Dubna, Russia Kurchatov Institute, Russia Charles University, Czech Republic North America (16)(~100) BNL, Caltech, George Mason Univ., LBNL, Iowa State Univ., Illinois Inst. Tech., Pi Princeton, RPI, RPISienna, UCB UC-Berkeley, UCLA, Univ. of Cincinnati, Univ. of Houston, Univ. of Wisconsin, Virginia i i Tech., Univ. of Illinois-Urbana-Champaign "#$%& '() *"+, Asia (19) (~130) IHEP, Beijing Normal Univ., Chengdu Univ. of Sci. and Tech., CGNPG, CIAE, Dongguan Polytech. Univ., Nanjing Univ., Nankai Univ., Shandong Univ., Shanghai Jiao Tong Univ., Shenzhen Univ., Tsinghua Univ., USTC, Zhongshan Univ., Univ. of Hong Kong, Chinese Univ. of Hong Kong, National Taiwan Univ., National Chiao Tung Univ., National United Univ. Total 38 Institutes,~ 240 collaborators! 45

The Daya Bay Reactor Neutrino Experiment

The Daya Bay Reactor Neutrino Experiment Lisa Whitehead Brookhaven National Laboratory for the Daya Bay Collaboration APS Meeting, Washington, D.C. Measuring 13 at a Reactor S jk =sin jk C jk =cos jk Neutrino