Results in Neutrino Oscillations from SuperKamiokande I

1
Current Status of RENO
NOW2008 (Conca Specchiulla, Italy)
Youngdo Oh Pohang University of science and
Technology (ydoh_at_postech.ac.kr)
2
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
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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
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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
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

• 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)
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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
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

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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