Results in Neutrino Oscillations from Super-Kamiokande I

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Current Status of RENO
NOW2008 (Conca Specchiulla, Italy)
Youngdo Oh Pohang University of science and
Technology (ydoh_at_postech.ac.kr)
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RENO Collaboration
(Reactor Experiment for Neutrino Oscillation)

• Chonnam National University
• Chonpook National University
• Dongshin University
• Gyeongsang National University
• Kyungpook National University
• Pusan National University
• Sejong University
• Seoul National University
• Sungkyunkwan University
• Pohang University of Science and Technology
• Institute of Nuclear Research RAS (Russia)
• Institute of Physical Chemistry and
  Electrochemistry RAS
• (Russia)
• 12institutes, 39 members http//neutrino.snu.
  ac.kr/RENO

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Yong Gwang Nucleat Power Plant

• Located in the west coast of southern
• part of Korea
• 400km from Seoul
• 6 reactors are lined up in roughly equal
  distances
• and span 1.3 km
• Total average thermal output 16.4GWth (2nd
• largest in the world)

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Schematic Setup of RENO at YongGwang
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Google Satellite View of YongGwang Site
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Schematic View of Underground Facility
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Schedule
We are here
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Comparison of Reactor Neutrino Experiments
Experiments Location Thermal Power (GW) Distances Near/Far (m) Depth Near/Far (mwe) Target Mass (tons)
Double-CHOOZ France 8.7 280/1050 60/300 10/10
RENO Korea 16.4 290/1380 120/450 15/15
Daya Bay China 11.6 360(500)/1985(1613) 260/910 40?2/80
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Rock sampling (DaeWoo Engineering Co.)
Rock samples from boring For chemical
composition, density, radioactivity
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Rock quality map

• Near detector site
• tunnel length 110m
• height 46.1m

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Tunnel Design
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Stress analysis for tunnel design
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Tunnel Construction is on going .
On-site office
Near tunnel
50m From entrance
Power Plant
Far tunnel
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RENO Detector

• Four concentric cylindrical parts
• Identical detectors for near and far
• Target and gamma catcher are
• filled with liquid scintillator
• aiming at detecting inverse beta decay
• 342 10-inch PMTs on the surface of buffer
• 67 10-inch PMTs on the VETO

total 450 tons
Inner Diameter (cm) vessel Inner Height (cm) Filled with Mass (tons)
Target Vessel 280 Acryl 320 Gd(0.1) LS 15.4
Gamma catcher 400 Acryl 440 LS 27.5
Buffer tank 540 Stainless steel 580 Mineral oil(LAB) 59.2
Veto tank 840 Steel 880 water 354.7
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Inverse beta decay in RENO Detector
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CAD views of RENO Detector
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Detector Design with MC Simulation

• RENO-specific MC simulation based on
  GLG4sim/Geant4
• ? Detailed detector design and drawings are
  completed

• Detector performance study Detector
  optimization with MC
• - Gamma catcher size
• - Buffer size
• - photo-sensor coverage (numbers of PMTs)
• - neutron tagging efficiency as a function
  of Gd concentration

• Reconstruction(vertex position energy) program
  written

• Systematic uncertainty sensitivity study

• Background estimation

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Systematic Errors
Systematic Source Systematic Source CHOOZ () RENO ()
Reactor related absolute normalization Reactor antineutrino flux and cross section 1.9 lt 0.1
Reactor related absolute normalization Reactor power 0.7 0.2
Reactor related absolute normalization Energy released per fission 0.6 lt 0.1
Number of protons in target H/C ratio 0.8 0.2
Number of protons in target Target mass 0.3 lt 0.1
Detector Efficiency Positron energy 0.8 0.1
Detector Efficiency Positron geode distance 0.1 -
Detector Efficiency Neutron capture (H/Gd ratio) 1.0 lt 0.1
Detector Efficiency Capture energy containment 0.4 0.1
Detector Efficiency Neutron geode distance 0.1 -
Detector Efficiency Neutron delay 0.4 0.1
Detector Efficiency Positron-neutron distance 0.3 -
Detector Efficiency Neutron multiplicity 0.5 0.05
combined combined 2.7 lt 0.5
Not final, under study
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RENO Expected Sensitivity
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GLoBES group workshop_at_Heidelberg Mentions talk
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RD Liquid scintillator (1)

• General Elements of Liquid Scintillator

Aromatic Oil Flour WLS Gd-compound
PC(Pseudocumene), PXE, LAB Mineral oil, Dodecane, Tetrdecane, LAB PPO, BPO Bis-MSB, POPOP 0.1 Gd compounds with CBX or BDK

• PC(20) Dodecane(80) PPO with bis-MSB or
  BPO
• 0.1 Gd compounds with CBX or BDK

• RD with the Russian INR/IPCE group (Gd powder
  supply)
• Recipe with various mixture performance (light
  yield, transmission attenuation lengths),
  availability, cost, etc.
• Design of purification system flow meter
• Long-term stability test
• Reaction with acrylic
• RD on LAB

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RD Liquid scintillator (2)
  Chemical elements HC M.W. (g/mol) Density (g/ml) Boiling Point Flash Point Viscosity _at_20? comments
decane C10H22   142.29 0.73 174 46 0.92cps Domestically available
dodecane C12H26 2.17 170.34 0.7493 216.2 71   Expensive
tetradecane C14H30   198.3922 0.767 253 99    
PC(TMB) C9H12 1.33 120.2 0.89(0.876) 169 48   Toxic Low FP
LAB C6H5 (CnH2n1) 1.66 233-237 0.86 275-307 130 5-10cps RD in progress Nontoxic Inexpensive
PXE C16H18 1.12 210.3 0.988 295 145 5.2cSt_at_40 Less toxic Supply limited
MO CnH2n2, n10-44     0.8   110 10-80cSt_at_40 Uncertainty in no. of protons
PC20dod80   2   0.78        
PXE20dod80    1.96   0.80   gt80    
PC20MO80       0.857        
PC40MO60       0.866        
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RD Liquid scintillator (3)
RD with LAB instead of PC/PXE Dodecane
CnH2n1-C6H5 (n1014)
Light yield measurement

• High Light Yield
• Good transparency (better than PC)
• High Flash point 147oC (PC 48oC)
• Environmentally friendly (PC toxic)
• Components well known (MO not well known)
• Domestically available Isu Chemical Ltd.

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RD Liquid scintillator (4)
Measurement of LAB Components with GC-MS
N10 N11 N12
N13
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RD Prototype Detector ( 2007 )

• The prototype detector was bulit
• to test properties liquid scintillator
• to validate the Monte Carlo Simulation
• model based on Geant4

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Prototype Detector Assembly
Acrylic vessels
Inner acrylic vessel
Mounting PMTs
Nitrogen flushing of LS
assembled prototype
Filling with liquid scintillator
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RD Mockup Detector ( 1 )

• By building mockup detector, we will answer the
  technical questions for final design of
• main detector.
• 40 scale to the main detector in size and 31
  10-inch PMTs
• To test
• Fabrication in Sepember 2008
• Data taking from October 2008, for next 6 months

diameter
height Target 60cm
60cm Gamma catcher 120cm 120cm Buffer
220cm 220cm

• - long tem stability and light transmittance of
  acrylic tank
• - source and light calibration
• PMT performance in mineral oil
• liquid handling system
• daq and data manipulation

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RD Mockup Detector ( 2 )

• PMT installation is done last week.
• DAQ and HV system ready
• Calibration system (this week)
• LS filling from next week
• Data taking from October for 6 months

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RD Mockup Detector ( 3 )
Source and light calibration system 137Cs,
60Co, 22Na, 252Cf , LED
LED
LED Trigger
LED Trigger
Pulse generator
Pulse generator
Diffuse ball
LED Trigger
Pulse generator
Liquid handling system
DAQ for mockup 400MHz FADC
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RD Mockup Detector ( 4 )

• Geant4 Monte Calro Simulation

Energy response of the mockup to the 137Cs(left)
60Co(right) at the center of the detector
Energy linearity (left) and energy
resolution(right) for positron
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Status Report of RENO

• RENO is suitable for measuring q13 (sin2(2q13)
  gt 0.02)

• Geological survey and design of access tunnels
  detector cavities are completed ? Excavation
  started

• RENO is under construction phase.

• Data taking is expected to start in early 2010.

• Mockup detector will operate soon.

• International collaborators are being invited.

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Back up slide
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Principle of Neutrino Detection
Prompt

• Use inverse beta decay (ve p e n)
• reaction process
• Prompt part
• subsequent annihilation of the positron
• to two 0.511MeV ?
• Delayed part
• neutron is captured
• 200ms w/o Gd
• 30ms w Gd
• Gd has largest n absorption cross section
• emits high energy g
• Signal from neutron capture
• 2.2MeV w/o Gd
• 8MeV w Gd
• Measure prompt signal delayed signal
• Delayed coincidence reduces
• backgrounds drastically

Delayed
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Study on ?-catcher size
RENO 70cm (94.28/-0.54) 60cm (92.98/-0.56)
Daya Bay 45cm 92 Chooz 70cm (94.6/-0.4)
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Reconstruction vertex energy

• Reconstructed vertex ? 8cm at the center of
  the detector

• Energy response and resolution

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Reconstruction of Cosmic Muons
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Calculation of Muon Rate at the RENO Underground
Jµ cm-2s-1 ltEµgt GeV
Far 250 m 2.910-5 91.7
Far 200 m 8.510-5 65.2
Near 70 m 5.510-4 34.3
Muon intensity at the sea level using modified
Gaisser parametrization MUSIC or Geant4 (the
code for propagating muon through rock)
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Calculation of g Background at the RENO
Underground

• g rate from rock Hz

Double CHOOZ Daya Bay RENO
Rock composition (K) 1.6 ppm (U) 2.00 ppm (Th) 5.0 ppm (K) 5 ppm (U) 10 ppm (Th) 30 ppm (K) 4.0 ppm (U) 4.8/-1.8 ppm (Th) 6.0/-2.2 ppm Sample from Chongpyung.
Detector DxH Size cm 230x246 (10.3 m3) 320x320 280x320
Shelding 17 cm Steel 2.5 m Water 0.45 m Oil 2.5 m Water
Rates (K) Hz (U) (Th) 0.86 0.89 0.98 0.26 0.65 2.6 (E?gt1 MeV) 0.21 0.53 1.74 (E?gt0.5 MeV)
Total rate 2.73 Hz 3.5 Hz 2.5 Hz
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Efforts for On-site Facility

• 0308, 2006 Project description to local
  government, residents, and NGOs (endorsed by
  local government)
• 03, 2007 Agreement between KHNP and SNU
• 0310, 2007 Geological survey and tunnel design
  are completed.
• 12, 2007 Public hearing for YG residents
• 01, 2008 Safety regulation established and
  accepted by the atomic energy department of MOST
• 0511, 2008 Tunnel construction