Youngdo OhPohang University of science and Technology

(ydoh@postech.ac.kr)

Current Status of RENONOW2008

(Conca Specchiulla, Italy)

RENO Collaboration

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

(Reactor Experiment for Neutrino Oscillation)

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)

Yong Gwang Nucleat Power Plant

Schematic Setup of RENO at YongGwang

Google Satellite View of YongGwang Site

Schematic View of Underground FacilitySchematic View of Underground Facility

Experimental Hall

Access Tunnel

Detector

(4m high ☓ 4m wide)

TunnelTunnel DetectorDetector

Schedule

Activities

Detector Design& Specification

Geological Survey& Tunnel Design

DetectorConstruction

Excavation &Underground Facility

Construction

DetectorCommissioning

2006 2007 2008 20093 6 9 12 3 6 9 12 3 6 9 12 3 6 9 12

We are here

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)

260/910 402/80

Rock sampling (DaeWoo Engineering Co.)Rock samples from boring

For chemical composition, density, radioactivity

• Near detector site: - tunnel length : 110m

- height : 46.1m

• Far detector site: - tunnel length : 272m- height : 168.1m

Rock quality map

Tunnel Design

연속체 안정성 검토

• 터널변위 및 응력해석

불연속체 안정성 검토

• 터널변위 및 응력해석

키블럭 안정성 검토

• 암반 블록파괴 검토

접속부 안정성 검토 확폭 및 수직터널 안정성 검토

• 터널변위 및 응력해석

콘크리트 구조 검토

• 구조물 안정성 검토 • 접속부변위 및 응력해석

Stress analysis for tunnel design

Tunnel Construction is on going ….

Near tunnel

Far tunnel

On-site office

Power Plant

50mFromentrance

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

total ~450 tons

Veto

Buffer

Target

-catcher

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

RENO Detector

Target :- Gd + LS

Gamma catcher : - LS

Buffer :- Non scintillating oil

Veto : - Water

Shielding :- Steel

Inverse beta decay in RENO Detector

pνe

e+γ(0.511MeV)

γ(0.511MeV)

n

Gd

γ

γ γ

γ

30μs

prompt signal

Delayed signal

E ~8MeV

CAD views of RENO Detector

Detector Design with MC Simulation

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

Systematic uncertainty & sensitivity study

Reconstruction(vertex position & energy) program written

Background estimation

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

Systematic Errors

Systematic Source CHOOZ (%) RENO (%)

Reactor related absolute

normalization

Reactor antineutrino flux and cross section

1.9 < 0.1

Reactor power 0.7 0.2

Energy released per fission 0.6 < 0.1

Number of protons in target

H/C ratio 0.8 0.2

Target mass 0.3 < 0.1

Detector Efficiency

Positron energy 0.8 0.1

Positron geode distance 0.1 -

Neutron capture (H/Gd ratio) 1.0 < 0.1

Capture energy containment 0.4 0.1

Neutron geode distance 0.1 -

Neutron delay 0.4 0.1

Positron-neutron distance 0.3 -

Neutron multiplicity 0.5 0.05

combined 2.7 < 0.5

Not final, under study

RENO Expected Sensitivity

GLoBES group workshop@Heidelberg – Mention’s talk

SK m2

R&D 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

R&D on LAB

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

R&D : Liquid scintillator (1)

 Chemicalelements

H:CM.W.

(g/mol)Density(g/ml)

Boiling Point

Flash Point

Viscosity@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

LABC6H5

(CnH2n+1)1.66 233-237 0.86 275-307 130 5-10cps

R&D in progressNontoxicInexpensive

PXE C16H18 1.12 210.3 0.988 295 145 5.2cSt@40 Less toxicSupply limited

MOCnH2n+2, n=10-44

    ~0.8   ~110 10-80cSt@40

Uncertainty in no. of protons

PC20dod80   2   0.78        

PXE20dod80 

  1.96   0.80   >80    

PC20MO80       0.857        

PC40MO60       0.866        

R&D : Liquid scintillator (2)

R&D with LAB instead of PC/PXE + Dodecane

Light yield measurement

CnH2n+1-C6H5 (n=10~14)

• 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.

R&D : Liquid scintillator (3)

Measurement of LAB Components with GC-MS

C16H26 C17H28 C18H30 C19H32

7.17% 27.63% 34.97% 30.23%

LAB : (C6H5)CNH2N+1

# of H [m-3] = 0.631 x 1029

H/C = 1.66

R&D : Liquid scintillator (4)

N=10 N=11 N=12 N=13

R&D : Prototype Detector ( 2007 )

The prototype detector was bulit

to test properties liquid scintillator to validate the Monte Carlo Simulation model based on Geant4

Prototype Detector Assembly

Acrylic vessels

Inner acrylic vessel

Nitrogen flushing of LS

Mounting PMTs

Filling with liquid scintillator

assembled prototype

R&D : 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 2008Data taking from October 2008, for next 6 months

- 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

diameter heightTarget 60cm 60cmGamma catcher 120cm 120cmBuffer 220cm 220cm

R&D : 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

R&D : Mockup Detector ( 3 )

Source and light calibration system: 137Cs, 60Co, 22Na, 252Cf , LED

DAQ for mockup – 400MHz FADCLiquid handling system

Pulse generator

LED Trigger

Pulse generator

LED Trigger

Pulse generator

LED

Diffuse ball

LED Trigger

R&D : Mockup Detector ( 4 )

Energy response of the mockupto the 137Cs(left) 60Co(right)at the center of the detector

Energy linearity (left) andenergy resolution(right) for positron

Geant4 Monte Calro Simulation

Status Report of RENO RENO is suitable for measuring 13 (sin2(213) > 0.02)

RENO is under construction phase.

Geological survey and design of access tunnels & detector cavities are completed → Excavation started

International collaborators are being invited.

Mockup detector will operate soon.

Data –taking is expected to start in early 2010.

Back up slide

p

νe

e+

e-

γ(0.511MeV)

γ(0.511MeV)

n

Gd

γ

γ γ

γ

E ~ 8MeV

30μs

prompt signal

Delayed signal

Principle of Neutrino Detection

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 ~200s w/o Gd ~ s w Gd Gd has largest n absorption cross section & emits high energy Signal from neutron capture ~2.2MeV w/o Gd ~ 8MeV w Gd Measure prompt signal & delayed signal “Delayed coincidence” reduces backgrounds drastically

8MeV30μs

1~8MeV

t

Signal Property

Gamma catcher thickness = 20cm

Gamma catcher thickness = 90cm

MeV MeVMeV

Study on -catcher size

Daya Bay45cm: 92%

Chooz70cm: (94.6+/-0.4)%

RENO70cm: (94.28+/-0.54)%60cm: (92.98+/-0.56)%

Gd capture

H capture

Reconstructed vertex: ~8cm at the center of the detector

Reconstruction : vertex & energy

1 MeV (KE) e+

Energy response and resolution:

%)14.00(E

)%03.074.7(EE

visible energy

3.01.29

/MeV 9.08.208

PMT coverage, resolution

~210 photoelectrons per MeV

|y|

y (

mm

)

Evis (MeV)

y

4 MeV (KE) e+

target

buffer

-catcher

Reconstruction of Cosmic Muons

~140cm

~40cm

~120cm

A

B

C

D

Veto(OD)

Buffer(ID)

pulse height timeOD PMTs

ID PMTs

Jμ [cm-2s-1] <Eμ> [GeV]

Far250 m 2.9×10-5 91.7

200 m 8.5×10-5 65.2

Near 70 m 5.5×10-4 34.3

Muon intensity at the sea level using modified Gaisser parametrization + MUSIC or Geant4 (the code for propagating muon through rock)

Calculation of Muon Rate at the RENO Underground

Calculation of Background at the RENO Underground

rate from rock [Hz]

Double CHOOZ

Daya Bay RENO

Rockcomposition

(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>1 MeV)

0.210.531.74(E>0.5 MeV)

Total rate ~2.73 Hz 3.5 Hz 2.5 Hz

•03~08, 2006 : Project description to local government, residents, and NGO’s (endorsed by local government)

•03, 2007 : Agreement between KHNP and SNU

•03~10, 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

•05~11, 2008 : Tunnel construction

Efforts for On-site Facility