Physics Symposium: Steve Kettell10/2/20071 The Daya Bay Reactor Antineutrino Experiment Steve Kettell BNL 1)Why Daya Bay? 2)Status/BNL involvement

Physics Symposium: Steve Kettell10/2/20072 ? The Last Mixing Angle:  13 U MNSP Matrix Maki, Nakagawa, Sakata, Pontecorvo Motivations to measure  13 Key to leptonic CP violation. How to extend the SM? What is  e fraction of 3 ? Is there  symmetry in mixing? ? atmospheric, K2K, MINOS reactor and accelerator MINOS, Double Chooz Daya Bay 0  SNO, solar SK, KamLAND  12 ~32°  23 ~45°  13 <12 °

Physics Symposium: Steve Kettell10/2/20073 Measuring sin 2 2  13 with Reactor Antineutrinos ~1.8 km ~ km Daya Bay, China Distance (km) PeePee nuclear reactor detector 1 detector 2  13 No dependence on  CP or matter effects Cost effective Rapid deployment sin 2 2   = 0.1 e disappearance probability

Physics Symposium: Steve Kettell10/2/20074 sin 2 2   < 0.17 (  m 2 31 = 2.5  10  3 eV 2 ) Daya Bay Strategy for  13 Limit on   from Chooz Daya Bay projected uncertainty! ChoozDaya Bay events3000/335d230k/3yr Mass5 ton80 ton Sys. Err2.7%0.2%

Physics Symposium: Steve Kettell10/2/20075 Daya Bay cores Ling Ao cores Ling Ao II cores (under construction) Daya Bay near Ling Ao near Far LS hall Entrance Construction tunnel Water hall liquid scintillator mineral oil Gd-LS Water shield Antineutrino Detector 4x20 ton (far)

Physics Symposium: Steve Kettell10/2/20076 The Physics is compelling! and a critical step to CP Measuring Beyond the Standard Model parameters  now! Diversity for Physics Department: complementary to LHC BNL has a rich tradition in physics: in both Physics and Chemistry departments (2 Nobel Prizes) Good match to the existing Physics Department effort on MINOS and future long-baseline experiment to measure CP violation in the neutrino sector. Priority with DOE - HEP Daya BNL

Physics Symposium: Steve Kettell10/2/20077 Sensitivity 3-year run with 80 t at far site Daya Bay near hall (40 t) Tunnel entrance Ling Ao near hall (40 t) Far hall (80 t) Rate and spectral shape Rate and spectral shape Relative detector systematic error of 0.2% Relative detector systematic error of 0.2% sin 2 2  13 <0.01 (90% CL) over allowed  m 2 90% C.L. Reactor pairs Currently allowed range of  m 2

Physics Symposium: Steve Kettell10/2/20078 Daya Bay Status APS multi-divisional study recommends reactor experiment (2004) CD-0: 11/2005 BNL formally joins collaboration 2/2006 NuSAG endorses DB goal and DB expt. as one option 2/2006 PAC endorses BNL involvement 3/23/2006 Successful DOE Physics Review 10/16/2006 P5 Roadmap: Recommends Daya Bay 10/2006 CD-1: 9/28/2007 today Start of Civil construction 10/2007 (groundbreaking 10/13) CD-2/3a baseline review 1/8/2008 at BNL CD-3b construction start Spring 2008 CD-4b start of full operations fall 2010

Physics Symposium: Steve Kettell10/2/20079 Summary The measurement of  13 at Daya Bay is a key part of the US HEP program This measurement is important in its own right and for future experiments to search for CP violation in neutrinos  All sites ready to take data in BNL is the largest US group on Daya Bay (2 nd overall after IHEP) Important part of the overall BNL neutrino plan (along with MINOS and Long Baseline/DUSEL)

Physics Symposium: Steve Kettell10/2/ Backup

Physics Symposium: Steve Kettell10/2/ Daya Bay collaboration North America (14)(50) BNL, Caltech, George Mason Univ., LBNL, Iowa state Univ. Illinois Inst. Tech., Princeton, RPI, UC-Berkeley, UCLA, Univ. of Houston, Univ. of Wisconsin, Virginia Tech., Univ. of Illinois-Urbana-Champaign, Asia (15) (86) IHEP, Beijing Normal Univ., Chengdu Univ. of Sci. and Tech., CGNPG, CIAE, Dongguan Polytech. Univ., Nanjing Univ.,Nankai Univ., Shenzhen Univ., Tsinghua Univ., USTC, Zhongshan Univ., Hong Kong Univ. Chinese Hong Kong Univ., Taiwan Univ., Chiao Tung Univ., National United Univ. Europe (3) (9) JINR, Dubna, Russia Kurchatov Institute, Russia Charles University, Czech Republic ~ 145 collaborators

Physics Symposium: Steve Kettell10/2/ BNL PAC BNL High Energy Nuclear Physics Program Advisory Committee meeting 3/23/06 The BNL neutrino group's presentation of the Daya Bay experiment and their involvement in it was very well received. In particular, the committee noted the crucial role BNL plays in R&D work for the Daya Bay experiment. In conjunction with the BNL Chemistry department, the group studies solubility of Gd in scintillator, and attenuation of light in the Gd doped scintillator. These R&D issues are at the heart of the potential success of both the Daya Bay and Braidwood reactor efforts. The committee recognizes and encourages the great synergy between the BNL physicists and chemists in the reactor program. PAC Membership: Stanley Brodsky, Donald Geesaman, Miklos Gyulassy, Barbara Jacak, Peter Jacobs, Bob Jaffe, Takaaki Kajita, James Nagle, Jack Sandweiss, Yannis Semertzidis

Physics Symposium: Steve Kettell10/2/ inverse  -decay in Gd-doped liquid scintillator: Arbitrary Flux Cross Section Observable Spectrum From Bemporad, Gratta and Vogel Detection of antineutrinos in liquid scintillator  e  p  e + + n (prompt)  + p  D +  (2.2 MeV) (delayed)  + Gd  Gd*  Gd +  ’s (8 MeV) (delayed) 50,000b 0.3b E   T e + + T n + (m n - m p ) + m e +  T e MeV Time- and energy-tagged signal is a good tool to suppress background events. Energy of e is given by: keV  0.1% Gd

Physics Symposium: Steve Kettell10/2/ Sensitivity to sin 2 2  13  0.01 High statistics: P owerful reactor cores Large target mass Control of systematic errors: Utilize multiple detectors at different baselines (near and far)  measure RATIOS Make detectors as nearly IDENTICAL as possible Careful and thorough calibration and monitoring of each detector Optimize baseline for best sensitivity and small residual reactor- related errors Possible to interchange detectors to further cancel most detector systematics

Physics Symposium: Steve Kettell10/2/ Antineutrino Detector Antineutrinos are detected via inverse  -decay in Gd-doped liquid scintillator (LS) Description: 3 zones: Gd-LS target (20 tons), LS gamma catcher, oil buffer 2 nested acrylic vessels, 1 stainless vessel 192 PMT’s on circumference of 5m  5m cylinder reflectors on endplates of cylinder energy resolution: 11.6% 12.5cm liquid scintillator mineral oil Gd-LS Water shield

Physics Symposium: Steve Kettell10/2/ Muon Veto - suppress spallation neutrons - require 99.5% efficiency Water shield (2.5m) - rock neutrons - radioactivity Muon System Water Cherenkov detectors with 963 PMTs in 3 sites 756 RPC chambers over top of 3 pools (6048 readout strips)

Physics Symposium: Steve Kettell10/2/ Ling Ao II NPP: 2  2.9 GW th Ready by Ling Ao NPP: 2  2.9 GW th Daya Bay Nuclear Power Facilities Daya Bay NPP: 2  2.9 GW th 1 GW th generates 2 ×  e per sec World’s 12 th most powerful (11.6 GW th ) 5 th most powerful by 2011 (17.4 GW th ) Adjacent to mountains, facilitates tunnels to underground labs with sufficient overburden to suppress cosmic rays (flexibility to move detectors)

Physics Symposium: Steve Kettell10/2/ BNL DB Activity in 2006 Joined collaboration in February 2006 Led (co-led) task forces: –Simulations: David Jaffe –Liquid Scintillator: Dick Hahn –Muon Veto: Laurie Littenberg –Antineutrino Detector: Steve Kettell Lead role in preparation for the DOE Physics Review. –BNL hosted the Director's Review. Proposal (DOE Physics Review): –leadership in drafting the Trigger/DAQ section –leadership of the Muon System section. –lead role in the coordination and drafting of the Installation, Operations and Project Development chapters and LS section. –lead role in editing and coordinating the Proposal. Coordination of the US effort on the muon system and LS. Coordination of the US design integration effort. Lead role in drafting the successful US FY06 R&D proposal.

Physics Symposium: Steve Kettell10/2/ Activity at BNL in 2007 BNL scientists have key roles in the Daya Bay Project: –Chief Scientist: Steve Kettell –Chief Engineer: Ralph Brown –Muon System L2 Manager: Laurie Littenberg –Installation and Integration L2 Managers: Ralph Brown –Liquid Scintillator L3 Manager: Minfang Yeh –Analysis and Simulation Software L3 Manager: David Jaffe –Co-leader of International Simulation effort: David Jaffe –Co-leader of International Liquid Scintillator Task Force: Dick Hahn CDR: –Chair of the Editorial Board and Editor-in-Chief: Steve Kettell –Members of the Editorial Board: David Jaffe and Laurie Littenberg –Technical advisor to the Editorial Board: Brett Viren –Lead Authors of 8 chapters: Steve Kettell, Laurie Littenberg, Ralph Brown. –Review committee: D. Jaffe, M. Bishai, B. Viren, R. Brown, L. Littenberg, D. Hahn. BNL is playing a lead role, along with LBNL and IHEP in the engineering design and integration, including the Civil Design specification. BNL is leading the effort to develop an installation plan BNL is playing a lead role in developing a Daya Bay safety plan.