the daya bay experiment kam-biu luk (uc berkeley & lbnl) for the daya bay collaboration p5...
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The Daya Bay Experiment
Kam-Biu Luk (UC Berkeley & LBNL)
forThe Daya Bay Collaboration
P5 Review, Fermilab, April 18, 2006
April 18, 2006 P5 Review (Kam-Biu Luk) 2
?
13The Last Unknown Neutrino Mixing Angle
2345
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?• Ue3 is a gateway to CP violation in neutrinos:
U Ue1 Ue2 Ue3
U1 U2 U 3
U1 U 2 U 3
0.8 0.5 Ue3
0.4 0.6 0.7
0.4 0.6 0.7
?
atmospheric,Accelerator
Reactor,accelerator
0SNO, solar SK,KamLAND
12 ~ 32° 23 = ~ 45° 13 = ?
P( e) - P( e) sin(212)sin(223)cos2(13)sin(213)sin
April 18, 2006 P5 Review (Kam-Biu Luk) 3
Current Knowledge of 13
Direct search
At m231 = 2.5 103 eV2,
sin22 < 0.15
allowed region
Experimentalallowed at 3
Nu
mb
er
of
pre
dic
tion
s
Theoretical predications
April 18, 2006 P5 Review (Kam-Biu Luk) 4
Recommendations
• APS Neutrino Study Group:
• Neutrino Scientific Assessment Group:
April 18, 2006 P5 Review (Kam-Biu Luk) 5
Limitations of Past and CurrentReactor Neutrino Experiments
Palo Verde, CHOOZTypical precision is 3-6%due to• 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%)
April 18, 2006 P5 Review (Kam-Biu Luk) 6
How To Reach A Precision of 0.01 ?
• Utilize a powerful nuclear power plant • Use large detectors to reduce statistical error • Use near and far detectors to minimize reactor-
related errors• Optimize baseline to have best sensitivity and further reduce any residual reactor-related
errors• Interchange near and far detectors to cancel
some of the detector systematic uncertainty• Use sufficient shielding to reduce background• Carry out comprehensive calibration to reduce
detector systematic error• Build almost identical detectors to reduce
detector-related systematic error
April 18, 2006 P5 Review (Kam-Biu Luk) 7
Goals And Approach• Utilize the Daya Bay nuclear power facilities to:
- determine sin2213 with a sensitivity of 1%- measure m2
31
• Adopt horizontal-access-tunnel scheme:
- mature and relatively inexpensive technology- flexible in choosing overburden- 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.
April 18, 2006 P5 Review (Kam-Biu Luk) 8
Where To Place The Detectors ?
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
0.1 1 10 100
Nos
c/Nn
o_os
c
Baseline (km)
P(e e ) 1 sin2 213 sin2 m312 L
4E
cos413 sin2 212 sin2 m21
2 L
4E
Large-amplitudeoscillation due to
12
Small-amplitudeoscillation due to 13
• Place near detector(s) close to reactor(s) to measure raw flux and spectrum of e, reducing reactor-related systematic
• Position a far detector near the first oscillation maximum to get the highest sensitivity, and also be less affected by 12
Sin2() = 0.1m2
31 = 2.5 x 10-3 eV2
Sin2() = 0.825m2
21 = 8.2 x 10-5 eV2
• Since reactor e are low-energy, it is a disappearance experiment:
April 18, 2006 P5 Review (Kam-Biu Luk) 9
Detecting Low-energy e
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.
• Energy of e is given by:
E Te+ + Tn + (mn - mp) + m e+ Te+ + 1.8
MeV 10-40 keV
• The reaction is the inverse -decay in Gd-doped liquid scintillator:
Arb
itra
ry
Flux Cross
Sectio
n
Observable Spectrum
From Bemporad, Gratta and Vogel
0.3b
50,000b
April 18, 2006 P5 Review (Kam-Biu Luk) 10
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. OlchevskiJoint Institute of Nuclear Research, Dubna, Russia
V.N. VyrodovKurchatov Institute, Moscow, Russia
B.Y. HsiungNational Taiwan University, Taipei
M. Bishai, M. Diwan, D. Jaffe, J. Frank, R.L. Hahn, S. Kettell, L. Littenberg, K. Li, B. Viren, M. YehBrookhaven National Laboratory, Upton, New York, U.S.
R.D. McKeown, C. Mauger, C. JillingsCalifornia Institute of Technology, Pasadena, California, U.S.
K. Whisnant, B.L. Young Iowa State University, Ames, Iowa, U.S.
W.R. Edwards, K. Heeger, K.B. LukUniversity of California and Lawrence Berkeley National Laboratory, Berkeley, California, U.S.
V. Ghazikhanian, H.Z. Huang, S. Trentalange, C. Whitten Jr.University of California, Los Angeles, California, U.S.
M. Ispiryan, K. Lau, B.W. Mayes, L. Pinsky, G. Xu,L. LebanowskiUniversity of HoU.S.ton, HoU.S.ton, Texas, U.S.
J.C. PengUniversity of Illinois, Urbana-Champaign, Illinois, U.S.
20 institutions, 89 collaborators
April 18, 2006 P5 Review (Kam-Biu Luk) 11
April 18, 2006 P5 Review (Kam-Biu Luk) 12
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
Ling Ao II NPP:2 2.9 GWth
Ready by 2010-2011
Ling Ao NPP:2 2.9 GWth
55 k
m
45 km
The Daya Bay Nuclear Power Facilities
Daya Bay NPP:2 2.9 GWth
1 GWth generates 2 × 1020 e per sec
• 12th most powerful in the world• Top five most powerful by 2011• Adjacent to mountain, easy to construct tunnels to reach underground labs with sufficient overburden to suppress cosmic rays
April 18, 2006 P5 Review (Kam-Biu Luk) 13
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 P5 Review (Kam-Biu Luk) 14
A Versatile Site
• Rapid deployment:- Daya near site + mid site - 0.7% reactor systematic error
• Full operation: (1) Two near sites + Far site (2) Mid site + Far site (3) Two near sites + Mid site + Far site Internal checks, each with different systematic
April 18, 2006 P5 Review (Kam-Biu Luk) 15
Geotechnical Survey
far
Dayanear
Lingaonear
midTopological survey:
Length: 2.5 km (S-N) Width: 450 m ~ 1.3 km (E-W) Area: 1.839 km2
Scale: Along tunnel 1:2000 Portal area 1:500
• Topological survey - complete• Geophysical survey
- complete• Bore drilling - complete
April 18, 2006 P5 Review (Kam-Biu Luk) 16
Planned tunnel
fault
Lingaonear
Dayanear
mid
mid
far
Weathering bursa
Geophysical Survey
Electrical Resistivitymethod
mid Lingaonear
April 18, 2006 P5 Review (Kam-Biu Luk) 17
bursa
Bore Drilling
LocationDrill
Depth (m)
ZK1 211
ZK2 210
Zk3 127
Zk4 133
April 18, 2006 P5 Review (Kam-Biu Luk) 18
April 18, 2006 P5 Review (Kam-Biu Luk) 19
(in the weathering bursa)
April 18, 2006 P5 Review (Kam-Biu Luk) 20
Findings of Geotechnical Survey
• No active or large fault
• Earthquake is infrequent
• Rock structure: massive and blocky granite
• Rock mass: most is slightly weathered or fresh
• Groundwater: low flow at the depth of the tunnel
• Quality of rock mass: 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:
April 18, 2006 P5 Review (Kam-Biu Luk) 21
Tunnel construction
• The total tunnel length is ~3 km• Preliminary cost estimate by professionals:
~$3K/m• Construction time is ~24 months• A similar tunnel exists on site as a reference
7.2 m
7.2 m
April 18, 2006 P5 Review (Kam-Biu Luk) 22
~350 m
~97 m
~98 m~210 m
Cosmic-ray Muon
• Apply modified Geiser parametrization for cosmic-ray flux at surface• Use MUSIC and mountain profile to estimate muon flux & energy
DYB LA Mid Far
Elevation (m) 97 98 208 347
Flux (Hz/m2) 1.2 0.73 0.17 0.045
Mean Energy (GeV)
55 60 97 136
April 18, 2006 P5 Review (Kam-Biu Luk) 23
What Target Mass Should Be?
Systematic error (per site): Black : 0.6% Red : 0.25% Blue : 0.12%
Solid lines : near+farDashed lines : mid+far
DYB: B/S = 0.5% LA: B/S = 0.4% Mid: B/S = 0.1% Far: B/S = 0.1%
m231 = 2 10-3 eV2
tonnes
April 18, 2006 P5 Review (Kam-Biu Luk) 24
Design of Antineutrino Detectors• Three-layer structure:
I. Target: Gd-loaded liquid scintillatorII. Gamma catcher: liquid scintillator, 45cmIII. Buffer shielding: mineral oil, ~45cm
• Possibly with diffuse reflection at ends. For ~200 PMT’s around the
barrel:vertex
14%~ , 14cm
(MeV)
E E
buffer
20t
Gd-doped
LS
gamma catcher
IsotopesPurity
(ppb)
20cm
(Hz)
25cm
(Hz)
30cm
(Hz)
40cm
(Hz)
238U(>1MeV) 50 2.7 2.0 1.4 0.8
232Th(>1MeV) 50 1.2 0.9 0.7 0.4
40K(>1MeV) 10 1.8 1.3 0.9 0.5
Total 5.7 4.2 3.0 1.7
Oil buffer thickness
April 18, 2006 P5 Review (Kam-Biu Luk) 25
3 zone
cut
Why three zones ?• Three zones:
- Construction of acrylic vessels is more involved - More background coming from the walls - Less fiducial mass
• Two zones:– Neutrino energy spectrum is distorted – Error of neutron efficiency due to energy scale and resolution: two zones: 0.4%, three zones 0.2%
2 zone
cut
– Using 4 MeV cut can reduce the error by a factor of two, but backgrounds from do not allow us to do so
CHOOZ
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Design of Shield-Muon Veto
• Detector modules enclosed by 2m of water to shield neutrons and
gamma-rays from surrounding rock• Water shield also serves as a Cherenkov veto• Augmented with a muon tracker: scintillator or RPCs• Combined efficiency of Cherenkov and tracker > 99.5%
2m ofwater
~0.05
Neutron background vs thickness of water
April 18, 2006 P5 Review (Kam-Biu Luk) 27
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Background
Near Site Far Site
Radioactivity (Hz) <50 <50Accidental B/S <0.05% <0.05%
Fast neutron background B/S
0.15% 0.1%
8He/9Li B/S 0.55% 0.25%
• Natural Radioactivity: PMT glass, Rock, Radon in the air, etc
• Slow neutron, and fast neutron
- Neutrons produced in rock and water shield (99.5% veto efficiency)
• Cosmogenic isotopes: 8He/9Li which can -n decay
- Cross section measured at CERN (Hagner et. al.)
- Can be measured in-situ, even for near detector with muon rate ~ 10 Hz.
• Use a modified Palo-Verde-Geant3-based
MC to model response of detector:
The above number is before shower-muon cut.
20t module
April 18, 2006 P5 Review (Kam-Biu Luk) 29
Systematic Uncertainty
Systematic error Chooz Daya Bay
Reaction Cross Section 1.9% 0, near-far cancellation
Energy released per fission 0.6% 0, near-far cancellation
Reactor Power 0.7% 0.06%, 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% Residual systematic error: ~ 0.2%
*• No Vertex cut.• Residual detection error is dominated by the neutron energy cut at 6 MeV arises mainly from the energy-scale uncertainties. (It is ~0.2% for a 1% energy-scale error at 6 MeV.• Positron energy cut is negligible.
April 18, 2006 P5 Review (Kam-Biu Luk) 30
• Daya Bay site Daya Bay site - baseline = 360 m- baseline = 360 m
- target mass = 40 tonne- target mass = 40 tonne
- B/S = ~0.5%- B/S = ~0.5%
• LingAo site LingAo site - baseline = 500 m- baseline = 500 m
- target mass = 40 tonne- target mass = 40 tonne
- B/S = ~0.5%- B/S = ~0.5%
• Far site Far site - baseline = 1900 m to DYB cores- baseline = 1900 m to DYB cores
1600 m to LA cores1600 m to LA cores
- target mass = 80 tonne- target mass = 80 tonne
- B/S = ~0.2%- B/S = ~0.2%
• Three-year run (0.2% Three-year run (0.2% statistical error)statistical error)
• Detector residual error = Detector residual error = 0.2%0.2%
• Use rate and spectral shapeUse rate and spectral shape
90% confidence level90% confidence level
Sensitivity of sin2213
2 n
ear +
far
near (4
0t) +
mid
(40 t)
1 year
Near-mid
April 18, 2006 P5 Review (Kam-Biu Luk) 31
Precision of m231
sin2213 = 0.02
sin2213 = 0.1
April 18, 2006 P5 Review (Kam-Biu Luk) 32
Major Items of U.S. Project Scope
• Muon tracking system (veto system)• Gd-loaded liquid scintillator• Calibration systems• PMT’s, base’s & control• Readout electronics & daq/trigger hardware
(partial)• Acrylic vessels (antineutrino detector)• Detector integration activities• Project management activities
April 18, 2006 P5 Review (Kam-Biu Luk) 33
U.S. Project Scope & Budget TargetsBudget
Institution 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 P5 Review (Kam-Biu Luk) 34
Details of Additional U.S. Scope
There are opportunities for the U.S. in other areas also:
These are items for which additional U.S. collaborators could participate
Details of additional university-based scopesoftware architecture 1000Offline computing architecture 1000Addn'l system test stands 700Water purification system 500Simulation 1000
Sub total: 4200
April 18, 2006 P5 Review (Kam-Biu Luk) 35
Overall Project Schedule
April 18, 2006 P5 Review (Kam-Biu Luk) 36
Prelim. Civil Construction Sched.
April 18, 2006 P5 Review (Kam-Biu Luk) 37
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 P5 Review (Kam-Biu Luk) 38
Funding Profile
Begin construction in China March 2007
CD-1 in U.S. November 2006
CD-2 in U.S. 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
$8MFY09
$14MFY10
$8M
April 18, 2006 P5 Review (Kam-Biu Luk) 39
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
April 18, 2006 P5 Review (Kam-Biu Luk) 40
April 18, 2006 P5 Review (Kam-Biu Luk) 41
Daya Bay
Ling Ao~1700 m
April 18, 2006 P5 Review (Kam-Biu Luk) 42
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 P5 Review (Kam-Biu Luk) 43
April 18, 2006 P5 Review (Kam-Biu Luk) 44