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The Daya Bay Experiment

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The Daya Bay Experiment

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  1. The Daya Bay Experiment • Motivation • Reactor anti-ne • Daya Bay Experiment • Collaboration/BNL involvement Steve Kettell BNL

  2. The U.S. should mount one multi-detector reactor experiment sensitive to edisappearance down to sin22θ13 ~ 0.01. Neutrinos • Connecting Quarks to the Cosmos: One of the eleven `profound questions’ addresses the mass and mixing of neutrinos. (2003) • Quantum Universe: “Detailed studies of the properties of neutrinos  their masses, how they mix, and whether they are Majorana particles will tell us whether neutrinos conform to the patterns of ordinary matter or whether they are leading us to the discovery of new phenomena.” (2004) recommendation of the APS  Study Group (11/04) NuSAG (2/28/06) Steve Kettell, BNL DOE HEP Review

  3. 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, (Bonnie Fleming, Frank Sculli) Steve Kettell, BNL DOE HEP Review

  4. The Last Unknown Neutrino Mixing Angle: 13 ? reactor and accelerator atmospheric, K2K SNO, solar SK, KamLAND 0 13 = ? 23 = ~ 45° 12 ~ 32° ? UMNSP Matrix Maki, Nakagawa, Sakata, Pontecorvo What ise fraction of 3? Is there  symmetry in neutrino mixing? Ue3 is the gateway to CP violationin neutrinos. Steve Kettell, BNL DOE HEP Review

  5. Measuring 13 with Reactor Neutrinos Pee Pee 13 Distance (km) Search for 13 in oscillation experiment Ue3 detector 1 nuclear reactor detector 2 ~1.8 km ~ 0.3-0.5 km Pure measurement of 13. Daya Bay, China Steve Kettell, BNL DOE HEP Review

  6. Detection of antineutrinos in liquid scintillator e  p  e+ + n(prompt) 0.3b  + p  D + (2.2 MeV) (delayed) 50,000b • + Gd  Gd*  Gd + ’s(8 MeV) (delayed) From Bemporad, Gratta and Vogel • Time- and energy-tagged signal is a good • tool to suppress background events. Arbitrary Observable n Spectrum • Energy ofe is given by: ETe+ + Tn + (mn - mp) + me+ Te+ + 1.8 MeV Cross Section Flux 10-40 keV • The reaction is inverse -decay in 0.1% Gd-doped liquid scintillator: Steve Kettell, BNL DOE HEP Review

  7. Current Knowledge of 13 q13 q12 Dm12 At m231 = 2.4  103 eV2, sin22 < 0.15 allowed region Established technique (e.g. Chooz)  with improvements for Daya Bay Limit on q13 from Chooz 2.7% without near detectors • limited statistics • reactor-related systematic errors: • - energy spectrum of e (~2%) • - time variation of fuel composition (~1%) • detector-related systematic error (1-2%) • background-related error (1-2%) Steve Kettell, BNL DOE HEP Review

  8. Requirements for improving the sensitivity to sin2213 0.01 • Higher statistics: • More powerful reactor cores • Larger target mass • Better 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 • Interchange detectors to cancel most detector systematics Steve Kettell, BNL DOE HEP Review

  9. Goals And Approach • Utilize the Daya Bay nuclear power facilities to: • - determine sin2213 with a sensitivity of 1% • - measure m231 • Employ horizontal-access-tunnel scheme: • - mature and relatively inexpensive technology • - flexible in choosing overburden and baseline • - relatively easy and cheap to add experimental halls • - easy access to underground experimental facilities • - easy to move detectors between different locations with good environmental control. • Adopt three-zone antineutrino detector design. Steve Kettell, BNL DOE HEP Review

  10. Daya Bay, China 45 km 55 km Steve Kettell, BNL DOE HEP Review

  11. The Daya Bay Nuclear Power Facilities • Powerful facilities (total thermal power): • 11.6 GW (now)  17.4 GW (2011) • comparable to Palo Verde, the most • powerful nuclear power plant in U.S. • Adjacent to mountain, easy to • construct tunnels to underground • labs with sufficient overburden to • suppress cosmic rays Ling Ao II NPP: 2  2.9 GWth Ready by 2010-2011 Ling Ao NPP: 2  2.9 GWth 1 GWth generates 2 × 1020 e per sec Daya Bay NPP: 2  2.9 GWth Steve Kettell, BNL DOE HEP Review

  12. Far site 1600 m from Ling Ao 2000 m from Daya Overburden: 350 m 910 m Mid site ~1000 m from Daya Overburden: 208 m 570 m 230 m (15% slope) 730 m 290 m (8% slope) Daya Bay Near 360 m from Daya Bay Overburden: 97 m Empty detectors: moved to underground halls through access tunnel. Filled detectors: swapped between underground halls via horizontal tunnels. Ling Ao Near 500 m from Ling Ao Overburden: 98 m Ling Ao-ll NPP (under const.) Ling Ao NPP Entrance portal Daya Bay NPP Total length: ~2700 m Steve Kettell, BNL DOE HEP Review

  13. 20 tonnes Gd-LS buffer gamma catcher Antineutrino Detector • Antineutrinos are detected via inverse -decay • in Gd-doped liquid scintillator (LS) • Description: • 3 zones: Gd-LS target (20 tonnes), • LS gamma catcher, oil buffer • 2 nested acrylic vessels, 1 stainless vessel • 200 8” PMT’s on circumference of 5m  5m cylinder • reflective surfaces on endplates of cylinder • energy resolution is 14%/E Steve Kettell, BNL DOE HEP Review

  14. Conceptual Design of Muon Veto rock muon tracker water 2m of water a conceptual design ~0.05 Neutron background vs. thickness of water • Detector modules enclosed by 2m of water to shield neutrons (and gamma-rays) • Water shield also serves as a Cherenkov veto • Augmented with a muon tracker: scintillator or RPC's • Combined efficiency of Cherenkov and tracker > 99.5% Steve Kettell, BNL DOE HEP Review

  15. Chris Laughton (FNAL) Pat Dobson (LBL) Joe Wang (LBL) Yanjun Sheng (IGG) Borehole drilling Findings of Geotechnical Survey U.S. experts in geology and tunnel construction assist geotechnical survey: • No active or large faults • Earthquakes are infrequent • Rock: massive and blocky granite • Rock mass: slightly weathered or fresh • Groundwater: low flow at tunnel depth • Quality of rock: stable and hard Good geotechnical conditions for tunnel construction Steve Kettell, BNL DOE HEP Review

  16. 7.2 m Tunnel construction • The total tunnel length is ~3 km • Preliminary civil construction design: ~$3K/m • Construction time is ~24 months (5 m/day) • A similar tunnel already exists on site 7.2 m Steve Kettell, BNL DOE HEP Review

  17. Background • Accidental Background: • Natural Radioactivity: PMT glass, Rock, Radon in the air, etc • Neutrons • Correlated Background: • Fast neutronsNeutrons produced in rock and water shield (99.5% veto efficiency) • Cosmic Ray production of 8He/9Li which can decay via -n emission For reference, 560(80) neutrino events per detector per day at the near(far) site Steve Kettell, BNL DOE HEP Review

  18. Systematic Uncertainty Statistical Error (3 years): 0.2% 2.8% (Chooz) Residual systematic error: ~ 0.2% 2.7% Steve Kettell, BNL DOE HEP Review

  19. Far (80t) Antineutrino detector modules, each with 20 tonne target mass Ling Ao near (40t) Horizontal tunnel Daya Bay near (40t) Tunnel entrance Sensitivity 3-year run with 80 t at far site Steve Kettell, BNL DOE HEP Review

  20. The Daya Bay Collaboration: China-Russia-U.S. 20 institutions, 89 collaborators Yu. Gornushkin, R. Leitner, I. Nemchenok, A. Olchevski Joint Institute of Nuclear Research, Dubna, Russia V.N. Vyrodov Kurchatov Institute, Moscow, Russia B.Y. Hsiung National Taiwan University, Taipei M. Bishai, M. Diwan, D. Jaffe, J. Frank, R.L. Hahn, S. Kettell, L. Littenberg, K. Li, B. Viren, M. Yeh Brookhaven National Laboratory, Upton, NY 11973-5000, U.S. R.D. McKeown, C. Mauger, C. Jillings California Institute of Technology, Pasadena, CA 91125, U.S. K. Whisnant, B.L. Young Iowa State University, Ames, Iowa 50011, U.S. W.R. Edwards, K. Heeger, K.B. Luk University of California and Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S. V. Ghazikhanian, H.Z. Huang, S. Trentalange, C. Whitten Jr. University of California, Los Angeles, CA 90095, U.S. M. Ispiryan, K. Lau, B.W. Mayes, L. Pinsky, G. Xu, L. Lebanowski University of Houston, Houston, Texas 77204, U.S. J.C. Peng University of Illinois, Urbana-Champaign, Illinois 61801, U.S. X. Guo, N. Wang, R. Wang Beijing Normal University, Beijing L. Hou, B. Xing, Z. Zhou China Institute of Atomic Energy, Beijing M.C. Chu, W.K. Ngai Chinese University of Hong Kong, Hong Kong J. Cao, H. Chen, J. Fu, J. Li, X. Li, Y. Lu, Y. Ma, X. Meng, R. Wang, Y. Wang, Z. Wang, Z. Xing, C. Yang, Z. Yao, J. Zhang, Z. Zhang, H. Zhuang, M. Guan, J. Liu, H. Lu, Y. Sun, Z. Wang, L. Wen, L. Zhan, W. Zhong Institute of High Energy Physics, Beijing X. Li, Y. Xu, S. Jiang Nankai University, Tianjin Y. Chen, H. Niu, L. Niu Shenzhen University, Shenzhen S. Chen, G. Gong, B. Shao, M. Zhong, H. Gong, L. Liang, T. Xue Tsinghua University, Beijing K.S. Cheng, J.K.C. Leung, C.S.J. Pun, T. Kwok, R.H.M. Tsang, H.H.C. Wong University of Hong Kong, Hong Kong Z. Li, C. Zhou Zhongshan University, Guangzhou Steve Kettell, BNL DOE HEP Review

  21. Steve Kettell, BNL DOE HEP Review

  22. Accomplishments at Feb Collaboration Meeting • Bylaws were ratified by the collaboration. • Institutional board, with one representative from each member institution and two spokespersons, was established. • Executive board was established: Y. Wang (China) A. Olshevski (Russia) C. Yang (China) K.B. Luk (U.S.) M.C. Chu (Hong Kong) R. McKeown (U.S.) Y. Hsiung (Taiwan) • Scientific spokespersons were chosen: Y. Wang (China), K.B. Luk (U.S.) • Project management in China and U.S. werecompared. • Initial discussions of construction project management. • Task forces were set up. Each task is led by at least one member from China and one from U.S. Steve Kettell, BNL DOE HEP Review

  23. Collaboration Communications • Weekly collaboration phone meetings • Weekly U.S. Daya Bay phone meetings • LBL serves as the hub for both phone meetings • BNL provides web archive for phone meetings • Several face-to-face collaboration meetings have been held in Beijing, Shenzhen, Hong Kong, and Berkeley. The most recent one was held at IHEP in February 2006. • Next collaboration meeting in Beijing, June 9-12, 2006. Steve Kettell, BNL DOE HEP Review

  24. Joint U.S.-China Task Forces International working groups with U.S.-China co-leadership for main detector systems and R&D issues established at the February collaboration meeting. • 1. Antineutrino Detector • Co-Chairs: S. Kettell (BNL, U.S.) • Y. Wang (IHEP, China) • 2. Calibration • Co-Chairs: R.D. McKeown (Caltech, U.S.) • X. Biao (CIAE, China) • 3. Communications • Co-Chairs: J. Cao (IHEP, China) • K.M. Heeger (LBNL, U.S.) • W. Ngai (CUHK, Hong Kong) • 4. Liquid Scintillator • Co-Chairs: R.L. Hahn (BNL, U.S.) • Z. Zhang (IHEP, China) • I. Nemchenok (Dubna, Russia) • 5. Muon Veto • Co-Chairs: L. Littenberg (BNL, U.S.) • K. Lau (Houston, U.S.) • Y. Changgen (IHEP, China) • 6. Offline Data Distribution and Processing • Co-Chairs: J. Cao (IHEP) • B. Viren (BNL) • 7. Project Management and Integration • Co-Chairs: B. Edwards (LBNL, U.S.) • S. Kettell (BNL, U.S.) • Y. Wang (IHEP, China) • H. Zhuang (IHEP, China) • 8. Simulation • Co-Chairs: J. Cao (IHEP, China) • C. Jillings (Caltech, U.S.) • 9. Tunneling and Civil Construction • Lead: C. Yang (IHEP, China) • U.S. Consultant: C. Laughton (FNAL, U.S.) Steve Kettell, BNL DOE HEP Review

  25. Why BNL? • The Physics is compelling! and a critical step to CP • BNL provides a strong National Laboratory presence to assure the success of the experiment. • BNL has a rich and storied tradition in n physics: in both the Physics and Chemistry departments • BNL Chemistry has been involved in liquid scintillator research for Daya Bay for 3 years • This experiment provides a bridge from the current Physics Department effort on MINOS to a long-baseline effort to measure CP violation in the neutrino sector. Steve Kettell, BNL DOE HEP Review

  26. BNL involvement in Daya Bay • Formally joined collaboration at Feb. 2006 meeting in Beijing • Member of Institutional Board (Kettell) • Lead of liquid scintillator task force (Hahn,Yeh) • Lead of muon veto task force (Littenberg, Diwan, Bishai) • Central detector task force (Kettell) • Simulations task force (Jaffe) • Project and other engineering resources available Steve Kettell, BNL DOE HEP Review

  27. BNL in Daya Bay • BNL is deeply involved in the muon tracker design • BNL is working with engineer from LBNL on antineutrino detector design and project management • BNL is looking to incorporate additional BNL engineering • One third of R&D request for BNL projects • As MINOS analysis effort matures, more effort directed to Daya Bay construction project and later to DB analysis VLBN E734 MINOS Steve Kettell, BNL DOE HEP Review

  28. U.S. R&D Plan Primary R&D Goals: • Ensure a strong U.S. contribution to the Daya Bay experiment. • Match the schedule of Chinese R&D and design. • Don’t let U.S. slow project down! • Optimize U.S. scope while minimizing cost. Full R&D funding in FY06 (and FY07): • Enable U.S. input to experiment design. • Timely technology choices. • Early determination of project cost and schedule. • Finalize preparations for CD-1 in about six months. DOE-HEP Daya Bay FY06 R&D Request 1/23/06, revised 1/31/06 Steve Kettell, BNL DOE HEP Review

  29. Gd-Loaded Liquid Scintillator BNL lead role: substantial R&D at BNL on metal loaded LS (funded by ONP + LDRD) • Avoid the chemical/optical degradation problems encountered in the Chooz and Palo Verde experiments Primary R&D Goals: • Study alternatives to PC (Low flashpoint: 48oC, health/environmental issues, attack acrylic) • For example, mixture of 20% PC and 80% dodecane • Current R&D is with Linear Alkyl Benzene, LAB, which is very attractive (high flashpoint:130o, biodegradable and environmentally friendly, readily available with tons produced by industry for detergents) • Successfully prepared Gd-LS in 100% LAB, with favorable properties (over Gd in PC) • Further studies needed to determine stability over time • Develop mass-production techniques to go from the current bench-top scale of kg (several liters) to tonnes (thousands of liters) Require stable (~years) Gd-LS with high light yield, long attenuation length. Explore alternatives to pseudocumene, PC. Evaluate chemical compatibility of Gd-LS with acrylic (detector vessel). Steve Kettell, BNL DOE HEP Review

  30. Absorbance at 430 nm Calendar Date Optical Attenuation of BNL Gd-LS Stable for ~500 days so far Gd-LS under UV light (in 10 cm cells) Steve Kettell, BNL DOE HEP Review

  31. Muon Veto/Tracker Understanding muon and spallation backgrounds: • High efficiency, redundant muon vetoes. • Tracking ability for systematic studies and event identification. • Primary R&D Goals: • Evaluate candidate technologies for muon tracker: • Plastic scintillator strips • Resistive Plate Chambers • Liquid scintillator modules • Evaluate candidate technologies for muon veto: • Water pool Cherenkov • Modular water Cherenkov • BNL Role • Subsystem in which U.S. is likely to take the lead  BNL has extensive experience in both plastic and liquid scintillator. Steve Kettell, BNL DOE HEP Review

  32. Antineutrino Detector • Measurement of sin2213  0.01 requires detector systems designed to • minimize systematic uncertainties. • Identical detector modules: • identical scintillator volumes, optical transparency. • facilitate calibration/monitoring system. • Moveable detectors: • design detectors for identical performance at all sites. • engineer support and movement structures. • time critical due to close interface with tunnel/cavern design. Primary R&D Goals: • Mechanical design of central detector. • Design of transportation and installation systems for detectors. • Identify vendors for fabricating acrylic vessels. BNL Role: • Engineering and leadership experience at LBNL and BNL. On the critical path (civil construction design contract). KamLAND 2005 Steve Kettell, BNL DOE HEP Review

  33. Site Development • Analyze core samples: input for detailed civil construction design studies. • Define surface building and underground halls (space and infrastructure). • Define liquid scintillator purification and handling (space and infrastructure). • Primary R&D Goals: • Define underground hall specifications in order to proceed to final civil design contract. • Interface between experiment design and hall design. • BNL Role: • Engineering and physics design experience • Specification of civil design is on the critical path; minimize delay and reduce risk for civil construction. KamLAND 2005 Steve Kettell, BNL DOE HEP Review

  34. Project Definition • Develop complete project scope and schedule (joint with China). • Define U.S. and Chinese deliverables (joint with China). • Develop U.S. cost and schedule ranges. • Build U.S. project team and organization. • Primary R&D Goals: • Develop the U.S. project scope, cost and schedule. • Coordinate with China on total project scope, cost and schedule. • BNL Role: • U.S. responsibility. Exploit project experience at LBNL and BNL. • Continue to develop coordination with Chinese effort. • Develop baseline project. • Develop overall experiment design. KamLAND 2005 Steve Kettell, BNL DOE HEP Review

  35. Initial definition of Project Scope U.S.-China primary responsibilities U.S. Scope • Muon tracking system (veto system) • Gd-loaded liquid scintillator • Calibration systems • Antinu Detector (Acrylic, PMT’s) • Electronics/DAQ/trigger hardware • Detector integration activities • Project management activities other contributions • Russia: liquid scintillator, calibration, and plastic scintillator • Taiwan: acrylic vessels and trigger • Hong Kong: calibration and data storage Steve Kettell, BNL DOE HEP Review

  36. U.S. Project Scope & Budget Steve Kettell, BNL DOE HEP Review

  37. Overall Project Schedule Steve Kettell, BNL DOE HEP Review

  38. Project Development • Schedule/activities over next several months: now – June now – summer now – Aug July – Nov Aug – Nov Determine scale of detector for sizing halls: Continue building strong U.S. team - key people: Conceptual design, scale & technology choices: Firm up U.S. scope, schedule & cost range: Write CDR, prepare for CD-1: Steve Kettell, BNL DOE HEP Review

  39. Funding Profile FY06 U.S. R&D $2M FY07 $3.5M FY08 U.S. Construction $10M FY09 $14M FY10 $8M CD-1 review November 2006 Begin construction in China March 2007 CD-2 review September 2007 Begin data collection January 2010 Measure sin2213 to 0.01 March 2013 Steve Kettell, BNL DOE HEP Review

  40. Summary and Prospects • The Daya Bay nuclear power facility in China and the mountainous topology in the vicinity offer an excellent opportunity for carrying out a measurement of sin2213 at a sensitivity of 0.01. • The Chinese funding agencies have agreed in principle to a request of RMB 150M to fund civil construction and ~half of the detector. • NuSAG endorsed U.S. participation in a 13 experiment, P5 is evaluating 13 experiments as part of the Roadmap, and we are hopeful for a positive decision by DOE. • BNL/LBNL submitted R&D request to DOE for FY06 in January 2006. • Have begun to form project leadership team with China: progress on organization, scope and cost. • Will complete a conceptual design of detectors, tunnels and underground facilities in 2006, aiming for CD1 review this year and a CD2 review in 2007. • In the ~3 months since BNL joined the Daya Bay collaboration we have made huge strides in defining and understanding the project and the U.S. scope. • Plan to commission a Fast Deployment plan in 2009, with full operation in 2010. Steve Kettell, BNL DOE HEP Review

  41. Backup Steve Kettell, BNL DOE HEP Review

  42. A Versatile Site • Full operation: • (A) Two near sites + Far site • (B) Mid site + Far site • (C) Two near sites + Mid site + Far site • Internal checks, each with different • systematic • Rapid deployment: • - Daya Bay near site + mid site • - 0.7% reactor systematic • error Steve Kettell, BNL DOE HEP Review

  43. ~350 m ~98 m ~208 m ~97 m Cosmic-ray Muon • Apply a modified Gaisser parameterization for cosmic-ray flux at surface • Use MUSIC and mountain profile to estimate muon flux & energy near site far site Steve Kettell, BNL DOE HEP Review

  44. Science Goals → Experiment Design → R&D • Reduce and control systematic errors: • “Identical” detectors at multiple sites • → detector design/construction, side-by-side comparisons • Detector performance - well-understood, stable • → materials/construction, calibration/monitoring • Reduce radioactivity background • → materials/construction, Gd-loaded scintillator • Reduce and measure cosmogenic backgrounds • → shielding, muon veto and tracking, DAQ system • Swap detectors • → horizontal tunnel system, locomotion equipment U.S. R&D tasks focused on achieving these goals Steve Kettell, BNL DOE HEP Review

  45. Background estimated by GEANT MC simulation Steve Kettell, BNL DOE HEP Review

  46. Detector-related Uncertainties w/Swapping → 0 → 0.006 → 0 → 0.06% Swapping: canreduce relative uncertainty further Absolute measurement Relative measurement Baseline: currently achievablerelativeuncertainty without R&D Goal: expectedrelativeuncertainty after R&D Steve Kettell, BNL DOE HEP Review

  47. Experimental Parameters Steve Kettell, BNL DOE HEP Review

  48. H/C ratio • CHOOZ claims 0.8% absolute based on multiple lab analyses (combustion) • We need only relative measurement • Double-CHOOZ claims 0.2% • Adopt 0.2% baseline • Adopt 0.1% goal R&D: measure via NMR or neutron capture Steve Kettell, BNL DOE HEP Review

  49. Target Volume • KamLAND: ~1% • CHOOZ: 0.02%? • Flowmeters – 0.02% repeatability • Baseline = 0.2% • Goal = 0.02% Steve Kettell, BNL DOE HEP Review

  50. Energy Cuts • CHOOZ = 0.8% absolute • Baseline 0.2% • Goal = 0.05% for • 2% energy calibration Steve Kettell, BNL DOE HEP Review