the daya bay experiment to measure 13
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The Daya Bay Experiment to Measure 13. Herbert Steiner UC Berkeley & LBNL On behalf of the Daya Bay Collaboration. Presented at the Erice School/Workshop on "Neutrinos in Cosmology,in Astro, in Particle and in Nuclear Physics” Erice/Sicily/Italy, September 21, 2009. Outline. • Overview - PowerPoint PPT PresentationTRANSCRIPT
The Daya Bay Experimentto Measure 13
Herbert Steiner UC Berkeley & LBNL
On behalf of the Daya Bay Collaboration
Presented at the Erice School/Workshop on "Neutrinos in Cosmology,in Astro, in Particle and in Nuclear Physics”
Erice/Sicily/Italy, September 21, 2009
Outline
• Overview• Physics• Detector• Backgrounds• Calibration• Schedule
The Daya Bay CollaborationEurope (3) (9)
JINR, Dubna, Russia
Kurchatov Institute, Russia
Charles University, Czech Republic
North America (15)(~89)BNL, Caltech, Cincinnati,
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 (19) (~135)IHEP, Beijing Normal Univ., Chengdu
Univ. of Sci. and Tech., CGNPG, CIAE,
Dongguan Polytech. Univ., Nanjing Univ., Nankai
Univ.,
Shandong Univ., Shanghai Jiaotong 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.
~ 233 collaborators
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55 k
m
45 km
Location of the Daya Bay Nuclear Power Plant
1 GWth generates 2 × 1020 e per sec
The Daya Bay Nuclear Power Plant
•12th most powerful in the world (11.6 GW)• Top five most powerful by 2011 (17.4 GW)• Adjacent to mountain, easy to construct tunnels to reach underground labs with sufficient overburden to suppress cosmic rays
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Total length: ~3100 m
Daya BayNPP, 22.9 GW
Ling AoNPP, 22.9 GW
Ling Ao-ll NPP(under construction)
22.9 GW in 2010
295 m Daya Bay Near site363 m from Daya BayOverburden: 98 m
Far site1615 m from Ling Ao1985 m from DayaOverburden: 350 m
4 x 20 tons target mass at far site
Ling Ao Near site~500 m from Ling AoOverburden: 112 m
81
0 m
465 m900 m
entrance
Filling hall
Constructiontunnel
Water hall
Daya Bay Layout
Horizontal TunnelTotal length 3200 m
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Excellent overburden to reduce cosmogenic background
Baselines (m):TopographyQuickTime™ and aTIFF (Uncompressed) decompressor
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Tunnel Construction Status (July ‘09)
Ling Ao Hall Tunnel Entrance
Far Hall
Daya Bay Near HallConstruction Tunnel
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Position SensitivityQuickTime™ and a
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How to measure 13?
Measured ratio of Rates
Proton Number
Ratio
DetectorEfficiency
Ratio
sin2213Filling Gd-LS and
Mass measurementCalibration Systems
MethodQuickTime™ and aTIFF (Uncompressed) decompressor
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Daya Bay: Goal and Approach• Utilize the Daya Bay nuclear power complex to:
determine sin2213 with a sensitivity of 0.01
by measuring deficit in e rate and spectral distortion.
0.985
0.99
0.995
1
0 1 2 3 4 5 6 7 8
Ratio(1.8 km/Predicted from 0.3 km)
Prompt Energy (MeV)
sin2213 = 0.01
2 3 4 5 6 7 8 9 10
energy (MeV)
Reduce systematic uncertainties: Reactor-related:
Optimize baseline for best sensitivity and lowest residual errors
Near and far detectors to minimize reactor-related errors
Detector-related: Use “Identical” pairs of detectors to do relative
measurement Fill all detectors with same batch of Gd-LS.
Comprehensive program in calibration/monitoring Side-by-side calibration
Background-related Go as deep as possible to reduce cosmic-induced
backgrounds Enough active and passive shielding
B/S ~0.4% Near B/S ~0.2% Far
How to measure sin2213 to 0.01QuickTime™ and aTIFF (Uncompressed) decompressor
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Sensitivity of Daya Bay
sin2213 < 0.01 @ 90% CL in 3 years of data taking
0 1 2 3 4 5
0.05
0.04
0.03
0.02
0.01
0.
Number of years of data taking
Sensi
tivit
y in s
in22 1
3 (
90
%C
L)
0.38% relative detector syst. uncertaintym2
31 = 2.5 103 eV2
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Reactor e
• Fission processes in nuclear reactors produce a
huge number of low-energy e
e/M
eV
/fiss
on
Resultant e spectrumknown to ~1%
3 GWth generates 6 x 1020 e per sec
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Detecting e in liquid scintillator
e p e+ + n (prompt)
+ p D + (2.2 MeV) (delayed) + Gd Gd*
Gd + ’s(8 MeV) (delayed)
• Time- and energy-tagged signal is a good tool to suppress background events.
• Detect inverse -decay reaction in 0.1% Gd-doped liquid scintillator:
0.3b
50,000b
• Energy of e is given by:
E Te+ + Tn + (mn - mp) + m e+ Te+ + 1.8
MeV 10-40 keV
Detection of e
Coincidence of prompt positron and delayed neutron signals
helps to suppress background events
Inverse -decay in Gd-doped liquid scintillator:Delayed Energy Signal Prompt Energy Signal
.
1 MeV 8 MeV 6 MeV 10 MeV
• Ee+(“prompt”) [1,8] MeV
• En-cap (“delayed”) [6,10] MeV• tdelayed-tprompt [0.3,200] s
n-p n-Gd
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Site Rate
DYB 840LA 740Far 90
Expected Antineutrino Rates
(Per Day per Module)
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Systematic Uncertainty Control
Sources of UncertaintyQuickTime™ and a
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BackgroundsQuickTime™ and a
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740
Layout in DBY HallQuickTime™ and aTIFF (Uncompressed) decompressor
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Daya Bay Antineutrino Detector
• 8 “identical”, 3-zone detectors
target mass: 20t per detectordetector mass: ~ 110tphotosensors: 192 PMTsenergy resolution: 12%/√E
e + p → e+ + n
acrylic tanksphotomultipliers
steel tank
calibration system
Gd-doped liquid scintillator
liquid scintillator
mineral oil
Gd-Liquid Scintillator Test Production
500L fluor-LABTwo 1000L 0.5% Gd-LAB 5000L 0.1% Gd-
LS
0.1% Gd-LS in 5000L tank
Daya Bay experiment uses 200 ton 0.1% gadolinium-loaded liquid scintillator (Gd-LS). Gd-TMHA + LAB + 3g/L PPO + 15mg/L bis-MSB
4-ton test batch production in April 2009.
Gd-LS will be produced in multiple batches but mixed in reservoir on-site, to ensure identical detectors.
Gd-LS stability in prototype
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Water Cherenkov Detector to Tag MuonsQuickTime™ and a
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CalibrationQuickTime™ and a
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FEE ANALOG CIRCUITS
INPUT STAGEINPUT STAGE
FAST ANALOG CIRCUIT for Analog TriggerFAST ANALOG CIRCUIT for Analog Trigger
THRESHOLD CIRCUIT for Multiplicity TriggerTHRESHOLD CIRCUIT for Multiplicity Trigger
SHAPING & ADC CIRCUIT for Charge MeasurementSHAPING & ADC CIRCUIT for Charge Measurement
Front End ElectronicsQuickTime™ and aTIFF (Uncompressed) decompressor
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Civil Construction
Control Room
Surface Assembly BldgEntrance
Inside tunnel
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Tunnel Construction Status
Pool Excavation in DBY Hall - Aug 09 Main Tunnels Join - June 09
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Detector Assembly
4-m vessel in the U.S.
Stainless steel tank in China
3-m acrylic vessel in Taiwan
SS Tank delivery Delivery of 4m AV Stainless steel tank in SAB
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AD Components QuickTime™ and aTIFF (Uncompressed) decompressor
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4-meter acrylic vessel arrives Unpacked 4-m acrylic vessel
PMT LadderMounting of non-reflecting panels
on ladder
AD Assembly
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Schedule
• 2003-2007: Proposal, R&D, engineering design etc.
• October 2007: Ground Breaking • March 2009: Surface Assembly Building occupancy • Summer 2010: Daya Bay Near Hall ready for data taking • Summer 2011: All near and far halls ready for data
taking
Three years’ data taking to reach full sensitivity.
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Thank You !
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