View
218
Download
0
Tags:
Embed Size (px)
Citation preview
The Daya Bay Experiment
Steve KettellBNL
1) Motivation2) Reactor anti-e
3) Daya Bay Experiment4) Collaboration/BNL involvement
April 18, 2006 Steve Kettell, BNL DOE HEP Review 2
• 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)
Neutrinos
The U.S. should mount one multi-detector reactor experiment sensitive to edisappearance down to sin22θ13 ~ 0.01.
April 18, 2006 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)
April 18, 2006 Steve Kettell, BNL DOE HEP Review 4
The Last Unknown Neutrino Mixing Angle: 13
UMNSP MatrixMaki, Nakagawa, Sakata, Pontecorvo
1 0 0
0 cos23 sin23
0 sin23 cos23
cos13 0 e iCP sin13
0 1 0
e iCP sin13 0 cos13
cos12 sin12 0
sin12 cos12 0
0 0 1
1 0 0
0 e i / 2 0
0 0 e i / 2i
What ise fraction of 3?Is there symmetry in neutrino mixing?
Ue3 is the gateway to CP violation in neutrinos.
?
U Ue1 Ue2 Ue 3
U1 U2 U 3
U1 U 2 U 3
0.8 0.5 Ue 3
0.4 0.6 0.7
0.4 0.6 0.7
?
atmospheric, K2K reactor and accelerator 0SNO, solar SK, KamLAND
12 ~ 32° 23 = ~ 45° 13 = ?
April 18, 2006 Steve Kettell, BNL DOE HEP Review 5
Pee 1 sin2 213 sin2 m312L
4E
cos4 13 sin2 212 sin2 m21
2L
4E
Distance (km)
Pee
Pe e
Measuring 13 with Reactor Neutrinos
Search for 13 in oscillation experiment
Ue3
~1.8 km
~ 0.3-0.5 kmPure measurement of 13.
nuclear reactor
detector 1
detector 2
13
Daya Bay, China
April 18, 2006 Steve Kettell, BNL DOE HEP Review 6
• Time- and energy-tagged signal is a good tool to suppress background events.
• Energy of e is given by:
E Te+ + Tn + (mn - mp) + me+ Te+ + 1.8 MeV 10-40 keV
• The reaction is inverse -decay in 0.1% Gd-doped liquid scintillator:
Arb
itra
ry
Flux Cross
Sectio
n
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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 7
Current Knowledge of 13
2.7% without near detectors
m
• 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%)
Established technique (e.g. Chooz) with improvements for Daya Bay
Limit on from Chooz
At m231 = 2.4 103 eV2,
sin22 < 0.15
allowed region
April 18, 2006 Steve Kettell, BNL DOE HEP Review 8
Requirements for improving the sensitivity to sin2213 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 9
Goals And Approach
• Utilize the Daya Bay nuclear power facilities to:- determine sin2213 with a sensitivity of 1%- measure m2
31
• 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.
April 18, 2006 Steve Kettell, BNL DOE HEP Review 10
Daya Bay, China
55 k
m
45 km
April 18, 2006 Steve Kettell, BNL DOE HEP Review 11
Ling Ao II NPP:2 2.9 GWth
Ready by 2010-2011
Ling Ao NPP:2 2.9 GWth
The Daya Bay Nuclear Power Facilities
Daya Bay NPP:2 2.9 GWth
1 GWth generates 2 × 1020 e per sec
• 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 12
Daya BayNPP
Ling AoNPP
Ling Ao-ll NPP(under const.)
Entrance portal
Empty detectors: moved to underground halls through access tunnel.Filled detectors: swapped between underground halls via horizontal tunnels.
Total length: ~2700 m
230 m(15% slope)290 m
(8% slope) 73
0 m
570 m
910 m
Daya Bay Near360 m from Daya BayOverburden: 97 m
Ling Ao Near500 m from Ling AoOverburden: 98 m
Far site1600 m from Ling Ao2000 m from DayaOverburden: 350 m
Mid site~1000 m from DayaOverburden: 208 m
April 18, 2006 Steve Kettell, BNL DOE HEP Review 13
buffer
20 tonnes
Gd-LS
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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 14
Conceptual Design of Muon Veto
• 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%
2m ofwater
~0.05
Neutron background vs. thickness of water
water
muon tracker
rock
a conceptual design
April 18, 2006 Steve Kettell, BNL DOE HEP Review 15
Findings of 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
Pat Dobson(LBL)
Chris Laughton (FNAL)
Joe Wang(LBL) Yanjun Sheng
(IGG)
U.S. experts in geology andtunnel construction assistgeotechnical survey:
Borehole drilling
April 18, 2006 Steve Kettell, BNL DOE HEP Review 16
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
7.2
m
April 18, 2006 Steve Kettell, BNL DOE HEP Review 17
Background
Near Site Far Site
Radioactivity (Hz) <50 <50
Accidental B/S <0.05% <0.05%
Fast neutron B/S 0.14%0.16% 0.08%0.1%8He/9Li B/S 0.41%±0.18% 0.02%±0.08%
• Accidental Background:• Natural Radioactivity: PMT glass, Rock, Radon in the air, etc• Neutrons
• Correlated Background:• Fast neutrons Neutrons 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 18
Systematic Uncertainty
Systematic error Chooz Daya BayReaction Cross Section 1.9% 0, near-far cancellation
Energy released per fission 0.6% 0, near-far cancellation
Reactor Power 0.7% 0.1%, near-far cancellation
Number of Protons 0.8% 0, detector swapping
Detection efficiency 1.5% ~0.2%, fewer cuts, detector swapping
Total 2.75% ~0.2%
Statistical Error (3 years): 0.2% 2.8% (Chooz) Residual systematic error: ~ 0.2% 2.7%
April 18, 2006 Steve Kettell, BNL DOE HEP Review 19
Sensitivity
Daya Baynear (40t)
Tunnel entrance
Ling Aonear (40t)
Far (80t)
Antineutrino detectormodules, each with 20 tonne target mass
Horizontal tunnel
3-year run with 80 t at far site
April 18, 2006 Steve Kettell, BNL DOE HEP Review 20
The Daya Bay Collaboration: China-Russia-U.S.
X. Guo, N. Wang, R. WangBeijing Normal University, Beijing
L. Hou, B. Xing, Z. ZhouChina Institute of Atomic Energy, Beijing
M.C. Chu, W.K. NgaiChinese 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. ZhongInstitute of High Energy Physics, Beijing
X. Li, Y. Xu, S. JiangNankai University, Tianjin
Y. Chen, H. Niu, L. NiuShenzhen University, Shenzhen
S. Chen, G. Gong, B. Shao, M. Zhong, H. Gong, L. Liang, T. XueTsinghua University, Beijing
K.S. Cheng, J.K.C. Leung, C.S.J. Pun, T. Kwok, R.H.M. Tsang, H.H.C. WongUniversity of Hong Kong, Hong Kong
Z. Li, C. ZhouZhongshan University, Guangzhou
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. PengUniversity of Illinois, Urbana-Champaign, Illinois 61801, U.S.
20 institutions, 89 collaborators
April 18, 2006 Steve Kettell, BNL DOE HEP Review 21
April 18, 2006 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. were compared.• 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.
April 18, 2006 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.
April 18, 2006 Steve Kettell, BNL DOE HEP Review 24
Joint U.S.-China Task Forces
1. Antineutrino DetectorCo-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. CommunicationsCo-Chairs: J. Cao (IHEP, China)
K.M. Heeger (LBNL, U.S.) W. Ngai (CUHK, Hong Kong)
4. Liquid ScintillatorCo-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 ProcessingCo-Chairs: J. Cao (IHEP)
B. Viren (BNL)
7. Project Management and IntegrationCo-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 ConstructionLead: C. Yang (IHEP, China)U.S. Consultant: C. Laughton (FNAL, U.S.)
International working groups with U.S.-China co-leadership for main detector systems and R&D issues established at the February collaboration meeting.
April 18, 2006 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 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.
April 18, 2006 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 27
• 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
MINOS
E734
BNL in Daya Bay
April 18, 2006 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 Request1/23/06, revised 1/31/06
R&D Tasks FY06 ($k)
1) Simulations 195
2) Liquid Scintillator 255
3) Antineutrino Detector 500
4) Calibration 370
5) Electronics 150
6) Muon Veto 419
7) Site Development 200
8) Project Definition 265
Total 2354
April 18, 2006 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)
1. Require stable (~years) Gd-LS with high light yield, long attenuation length.2. Explore alternatives to pseudocumene, PC.3. Evaluate chemical compatibility of Gd-LS with acrylic (detector vessel).
April 18, 2006 Steve Kettell, BNL DOE HEP Review 30
Calendar Date
Ab
sorb
ance
at
430
nm
Optical Attenuation of BNL Gd-LS
Gd-LS under UV light (in 10 cm cells)
Stable for ~500 days so far
April 18, 2006 Steve Kettell, BNL DOE HEP Review 31
Muon Veto/Tracker
Understanding muon and spallation backgrounds:
1. High efficiency, redundant muon vetoes.
2. 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.
April 18, 2006 Steve Kettell, BNL DOE HEP Review 32
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).
Antineutrino Detector
Measurement of sin2213 0.01 requires detector systems designed tominimize systematic uncertainties.
1. Identical detector modules:• identical scintillator volumes, optical transparency.• facilitate calibration/monitoring system.
2. 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.
KamLAND 2005
April 18, 2006 Steve Kettell, BNL DOE HEP Review 33
Site Development
1. Analyze core samples: input for detailed civil construction design studies.
2. Define surface building and underground halls (space and infrastructure).
3. 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 34
Project Definition
1. Develop complete project scope and schedule (joint with China).2. Define U.S. and Chinese deliverables (joint with China).3. Develop U.S. cost and schedule ranges.4. 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 35
Initial definition of Project 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 Majority Responsibility
WBS Description China US
4 DAQ, Trigger, Online & Offline Hardware ĆDAQ & trigger board co-design, board manufacture, racks, Ćmonitoring & controls hardware, some on-line hardware ĆDAQ & trigger board co-design, crates, cables, on-line hardware Ćoff-line hardware & data archiving in US, system test platform Ć
5 DAQ, Trigger, Online & Offline Software Ć ĆOverall software architecture, DAQ & trigger software, shared sharedon-line & off-line software, simulations software shared sharedMonitoring & controls software Ć
6 Conventional Construction & Equipment ĆTunnels, entrances, experimental halls, underground utilities, Ćsafety systems, surface facilities Ć
7 System Integration Ć Ć
8 Project Management Ć Ć
Majority ResponsibilityWBS Description China US
1 Central Detector ĆSystem design, steel vessels, unloaded LS, mineral oil, Ćreadout electronics co-design, electronics mfg, safety Ćsystems, racks, assembly & installation ĆAcrylic vessels, PMT's & support structure, Gd loaded LS, Ć LS purification system, locomotion system, readout Ćelectronics co-design, cables, crates Ć
2 Veto Detector ĆSystem design, muon tracker system, supplemental water Ćveto PMT's, muon tracker assy & test ĆWater veto system hardware, compensation coils, readout Ćelectronics mfg, safety syst, water veto assy & test Ć
3 Calibration & Monitoring Systems ĆAutomated deployment system & glove box, laser sources, Ćmonitoring system & system test ĆManual calibration sys & glovebox, LED sources, radioactive Ćcalib. sources, low-background source & matls counting syst Ć
U.S.-China primary responsibilitiesU.S. Scope
• Russia: liquid scintillator, calibration, and plastic scintillator• Taiwan: acrylic vessels and trigger• Hong Kong: calibration and data storage
other contributions
April 18, 2006 Steve Kettell, BNL DOE HEP Review 36
U.S. Project Scope & Budget
BudgetInstitution WBS element Lead? target ($K) Comments
BNL Muon tracker system Y 5,000 joint with university groupsGd-loaded liquid scintillator Y 1,500 may include LS purification system
California Institute Techology Calibration systems Y 2,000 joint with univ groups & LBNL
University of Houston DAQ hardward & software 1,000 joint with univ groups & LBNL
LBNL Project management Y 1,700System integration Y 1,700 joint with BNLPMT's, bases & control Y 3,000 joint with university groupsLocomotion & cranes Y 600 joint with BNLReadout & trigger electronics 1,000 joint with univ groups & BNLAcrylic Vessels Y 2,000
U. Ill at Urbana-Champaign, addn'l university-based scope 4,200 see next slide for detailsIowa State University,UCLA + other universities
Other Necessary ItemsCommon fund 2,000Project contingency ~30% 7,000
Total:Total: 32,700
April 18, 2006 Steve Kettell, BNL DOE HEP Review 37
Overall Project Schedule
April 18, 2006 Steve Kettell, BNL DOE HEP Review 38
Project Development
• Schedule/activities over next several months:
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:
now – June
now – summer
now – Aug
July – Nov
Aug – Nov
April 18, 2006 Steve Kettell, BNL DOE HEP Review 39
Funding Profile
CD-1 review November 2006
Begin construction in China March 2007
CD-2 review September 2007
Begin data collection January 2010
Measure sin2213 to 0.01 March 2013
FY06 U.S. R&D $2M FY07 $3.5MFY08 U.S. Construction $10MFY09 $14MFY10 $8M
April 18, 2006 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 sin2213 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.
April 18, 2006 Steve Kettell, BNL DOE HEP Review 41
Backup
April 18, 2006 Steve Kettell, BNL DOE HEP Review 42
A Versatile Site
• Rapid deployment:- Daya Bay near site + mid site - 0.7% reactor systematic error
• 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 43
~350 m
~97 m
~98 m~208 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
DYB LingAo Mid Far
Elevation (m) 97 98 208 347
(m.w.e.) 280 280 560 930
Flux (Hz/m2) 1.2 0.94 0.17 0.045
Mean Energy (GeV) 55 55 97 136
near site
far site
April 18, 2006 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
U.S. R&D tasks focused on achieving these goals
• 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 45
Background estimated by GEANT MC simulation
Near far
Neutrino signal rate(1/day) 560 80
Natural backgrounds(Hz) 45.3 45.3
Single neutron(1/day) 24 2
Accidental BKG/signal 0.04% 0.02%
Correlated fast neutron Bkg/signal 0.14% 0.08%
8He+9Li BKG/signal 0.5% 0.2%
April 18, 2006 Steve Kettell, BNL DOE HEP Review 46
Detector-related Uncertainties
Baseline: currently achievable relative uncertainty without R&D Goal: expected relative uncertainty after R&D
Absolutemeasurement
Relativemeasurement
→ 0→ 0.006
→ 0.06%
w/Swapping
→ 0
Swapping: can reduce relative uncertainty further
April 18, 2006 Steve Kettell, BNL DOE HEP Review 47
Experimental Parameters
April 18, 2006 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
April 18, 2006 Steve Kettell, BNL DOE HEP Review 49
Target Volume
• KamLAND: ~1%• CHOOZ: 0.02%?
• Flowmeters – 0.02% repeatability
Baseline = 0.2% Goal = 0.02%
April 18, 2006 Steve Kettell, BNL DOE HEP Review 50
Energy Cuts
• CHOOZ = 0.8% absolute• Baseline 0.2%• Goal = 0.05% for
2% energy calibration
April 18, 2006 Steve Kettell, BNL DOE HEP Review 51
Energy Cuts
KamLAND calibration data:
April 18, 2006 Steve Kettell, BNL DOE HEP Review 52
Time Cuts
Neutron time window uncertainty:
t = 10 ns 0.03% uncertainty Use common clock for detector modules
Baseline = 0.1% Goal = 0.03%
April 18, 2006 Steve Kettell, BNL DOE HEP Review 53
H/Gd ratio
CHOOZ measured to ±0.5s =0.01% for t1=0.2s
Measure neutron capture time
April 18, 2006 Steve Kettell, BNL DOE HEP Review 54
Livetime
• Measure relative livetimes using accurate common clock• Should be negligible error (note SNO livetime error of ~10-5
April 18, 2006 Steve Kettell, BNL DOE HEP Review 55
What Have We Learned From Chooz?
CHOOZ Systematic Uncertainties
Reactor flux & spectrumDetector Acceptance
2%1.5%
Total 2.7%
5 t Gd-loaded liquid scintillatorto detect
L = 1.05 km
D = 300 mwe
P = 8.4 GWthRate: ~5 events/day/t (full power) including 0.2-0.4 bkg/day/t
e + p e+ + n
e+ + e- 2 x 0.511 MeV n + Gd 8 MeV of s; ~ 30 s
~3000 e candidates(included 10% bkg) in335 days
April 18, 2006 Steve Kettell, BNL DOE HEP Review 56
Num
ber o
f Ant
i-neu
trino
s per
0.05
MeV
per
fissio
n0
2
4
6
8
10
0 2 4 6 8 10
Total
Cro
ss S
ectio
n (10
-40
cm2 )
Energy (MeV)
Cross Section
dN/dE
Observed Events (arbitrary scale)
Reactor anti-e
For 235U, for instance, an average of 6 es are produced per fission (~200 MeV).
e/M
eV
/fiss
ion
3 GWth generates 61020 e per sec
P(e e )1
- 42
April 18, 2006 Steve Kettell, BNL DOE HEP Review 57
Time Variation of Fuel Composition
Typically known to ~1%
235U
238U239Pu
241Pun
orm
aliz
ed
flu
x t
imes
cross
sect
ion
(arb
itra
ry u
nit
s)
0
0
.5
1
1.5
2
2.5
3
3
.5
1 2 3 4 5 6 7 8 9 10E (MeV)
April 18, 2006 Steve Kettell, BNL DOE HEP Review 58
Calibration
• Radioactive Source 137Cs, 22Na, 60Co, 54Mn, 65Zn , 68Ge, Am-Be
252Cf, Am-Be
• Gamma generator
p+19F→ α+16O*+6.13MeV; p+11B→ α+8Be*+11.67MeV
• Backgrounds
40K, 208Tl, cosmic-induced neutrons, Michel’s electrons, …
• LED calibration
KI & CIAE
Hong Kong
April 18, 2006 Steve Kettell, BNL DOE HEP Review 59
What Target Mass Should Be?
Systematic errorBlack : 0.6%
DYB: B/S = 0.5% LA: B/S = 0.4% Far: B/S = 0.1%
m231 = 2 10-3 eV2
tonnes
(3 year run)
Red : 0.25% (baseline goal)Blue : 0.12%
April 18, 2006 Steve Kettell, BNL DOE HEP Review 60
Sensitivity
For 3 years
With four 20-t modules at the far site and two 20-t modules at each near site:
April 18, 2006 Steve Kettell, BNL DOE HEP Review 61
Precision of m231
sin2213 = 0.02
sin2213 = 0.1
April 18, 2006 Steve Kettell, BNL DOE HEP Review 62
Synergy of Reactor and Accelerator Experiments
Δm2 = 2.5×10-3 eV2 sin2213 = 0.05
Reactor experiments can help in Resolving the 23 degeneracy
(Example: sin2223 = 0.95 ± 0.01)
90% CL
Reactor w 100t (3 yrs) + Nova Nova only (3yr + 3yr) Reactor w 10t (3yrs) + Nova
90% CL
McConnel & Shaevitz, hep-ex/0409028
90% CL
Reactor w 100t (3 yrs) +T2K T2K (5yr,-only) Reactor w 10t (3 yrs)+T2K
Reactor experiments providea better determination of 13