On behalf of the DayaBay collaboration Virginia Polytechnic Institute and State University Joseph ykHor YuenKeung Hor Virginia Tech Daya Bay collaboration APS SouthEast meeting 2009 ID: 627713
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Slide1
Daya Bay Reactor Neutrino ExperimentOn behalf of the DayaBay collaboration
Virginia Polytechnic Institute and State UniversityJoseph ykHor
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
1Slide2
Table of Content
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS
SouthEast meeting 2009
2
Physics Goal
Relative measurement & disappearance probability
Baseline
& detector design
Sensitivity
Current status, schedule and dates
Background and energy cutSlide3
Physics Goal
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
3
Angra, Brazil
R&D phase
Diablo Canyon, USA
Braidwood, USA
Double Chooz, France
sin
2
2
13
~
0.03
Krasnoyarsk, Russia
Daya Bay, China
sin
2
2
13
~
0.01
8
proposals
4 cancelled
3
in progress
KASKA, Japan
RENO, Korea
sin
2
2
13
~
0.03Slide4
Physics Goal
Determine θ
13 better than any past experiments
θ
23
~ 45
o
θ
12
~ 35
o
Super K + Accelerator
KamLand
+ Solar
+ atmospheric
CP-phase + small
θ
13
DayaBay
Double
Chooz
PMNS Matrix Parameterization:
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
4
Neutrinoless
double beta decaySlide5
Relative measurement & disappearance probability
near detectors measure
e flux and spectrum to
reduce reactor-related systematic uncertainties
far detector
at the oscillation maximumprovides the highest sensitivity
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
5Slide6
Relative measurement & disappearance probability
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 20096
Ratio of measured event rate from far and near site detectors
Ratio of number of protons in
Gd
-LS.
Obtained by mass
flow measurements
Ratio of the detector efficiency
Obtained by calibration
Probability ratio
determine
sin
2
(2
θ
13
)
ν
e
distance L ~
1.8
km
~ 0.4
kmSlide7
Baseline & detector design YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
7
Ling
Ao
II NPP:
2
2.9
GW
th
Ready by 2010-2011
Ling
Ao
NPP:
2
2.9
GW
th
1
GW
th
generates 2 × 10
20
e
per sec
currently running at
11.6 GW one of the 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 raysSlide8
Baseline & detector design
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 20098
Deep down the mountain to suppress
cosmogenic
background
Deploy identical detectors in all sites to isolate systematic uncertainties
Optimize baseline distance for disappearance oscillation
Daya
Bay Near site
363 m from
Daya
Bay
Overburden: 98 m
Ling
Ao
Near site
~500 m from Ling
Ao
Overburden: 112 m
Far site
1615 m from Ling
Ao
1985 m from
Daya
Bay
Overburden: 350 m
Slide9
Baseline & detector design
Antineutrino Detector(AD)
Automatic calibration systemTop and bottom reflectors
192 8” PMTs
Three-zone design:
Gd-doped LS, 20 tons
Inner acrylic vessel
LS as Gamma Catcher, 20 tons
Outer acrylic vessel
Mineral oil as buffer, 40 tons
Stainless steel tank
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
9
5 m
5 mSlide10
Baseline & detector design
Muon tagging
Shielding of background radiationRPC as
muon veto on top of water
Cherenkov
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
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Resistive plate chambers (RPC)
AD
2.5m water shield
8” PMTs
289 PMTs in near site
384 PMTs in far siteSlide11
Sensitivity
sin22θ
13 < 0.008
@ 90% CL
after 3 years of data taking
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
11
0 1 2 3 4 5
0.05
0.04
0.03
0.02
0.01
0.
Number of years of data taking
Sensitivity in sin
2
2
13
(90%CL)
Rapid
convergence
Δ
m
31
2
=2.5 x 10
-3
eV
2Slide12
Sensitivity YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
12
sin
2
2
θ
13
<
0.008
@ 90% CL
after 3 years of data takingSlide13
Current status, schedule and dates YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
13
CD-0 (DOE Mission Need): 11/2005
Daya
Bay proposed at OHEP Briefing 4/2006
Successful Physics Review 10/16/06
CD-1 site selection approved 9/2007
Groundbreaking for civil construction 10/2007
CD-2 & 3a Baseline approved 3/2008
CD-3b Construction start 8/2008
Occupancy of SAB 3/2009
Occupancy of first underground halls
, 2009
Expected start of first operations,
2010
Full operations start,
2011Slide14
Current status, schedule and dates
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
14Slide15
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
15
Current status, schedule and dates
Red indicates current construction progressSlide16
DayaBay experiment
is the most sensitive
θ13
experiment under construction
Specifically designed to achieve the sensitivity of
sin2 (2
θ
13
)
down
to 0.01(goal) at 90% C.L. and 0.008(projected) in three years of data taking
It is now on track to
take
initial data in the
next year and become fully operational in 2 years
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
16
SummarySlide17
The EndThank You
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
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Back up
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 200918Slide19
Back up
Accidental coincidence:
natural radioactivity
neutrons from cosmic
muons
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
19
Correlated events:
Fast neutron capture + recoil proton
Beta + neutron decay from Helium & LithiumSlide20
Back up
Energy spectrum of two processes in inverse-beta decay
YuenKeung, Hor Virginia Tech. Daya Bay collaboration APS SouthEast meeting 2009
20
Prompt Energy Signal
1 MeV
8 MeV
6 MeV
10 MeV
Delayed Energy Signal
e
p
e
+
+
n
(prompt)
+ p
D
+
(2.2
MeV
)
(delayed)
+ Gd
Gd*
Gd
+
’s
(8 MeV)
(delayed)
0.3b
50,000b