Soo-Bong KimSeoul National Univ.

RENO for Neutrino Mixing Angle 13

(“Neutrinos in Cosmology, in Astro-, Particle- and Nuclear Physics”

Sep. 16-24, 2009, Erice/Sicily, Italy)

New Reactor Neutrino 13 Experiment

Lower background - Improved detector design - Increased overburden

CHOOZ : Rosc = 1.01 ± 2.8% (stat) ± 2.7% (syst)

Larger statistics - More powerful reactors (multi-core) - Larger detection volume - Longer exposure

Smaller experimental errors - Identical multi detectors

→ Obtain ~1% precision !!!

arXiv:0905.3549v2, Fogli et. al.

Hint of 13 >0 from different data sets and combinations : 1 range

Detection of Reactor Neutrinos

8MeV30μs

1~8MeV

t

Signal Propertyp

νe

e+

e-

γ(0.511MeV)

γ(0.511MeV)

n

Gd

γ

γ γ

γ

E ~ 8MeV

30μs

prompt signal

Delayed signal

data from CHOOZ hep-ex/0301017v1

(1) 0.7<Eprompot <9MeV (2) 5<Edelayed <11MeV

(3) 1μs<ΔT <200μs

e+ energy n capture energy

RENO Collaboration (11 institutions and 40 physicists) Chonnam National University Dongshin University Gyeongsang National University Kyungpook National University Pusan National University Sejong University Seoul National University Sungkyunkwan University Seokyeong University Institute of Nuclear Research RAS (Russia) Institute of Physical Chemistry and Electrochemistry RAS (Russia)

+++ http://neutrino.snu.ac.kr/RENO

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 17.3 290/1380 120/450 16/16

Daya Bay China 11.6 360(500)/1985(1613) 260/910 402/80

Schematic Setup of RENO at YongGwang

Google Satellite View of YongGwang Site

Schematic View of Underground FacilitySchematic View of Underground Facility

100m 300m

70m high

200m high

1,380m

290m Far Detector

Near Detector Reactor

s

RENO Detector

Inner Diameter (cm)

Inner Heigh

t (cm)

Filled with

Mass (tons

)

Target Vesse

l

280 320 Gd(0.1%) + LS

16.1

Gamma catch

er

400 440 LS 28.5

Buffer tank

540 580 Mineral oil

64.4

Veto tank

840 880 water 352.6total ~460 tons

421(354+61) 10” PMTs

Schedule

Summary of Construction Status•03~10, 2007 : Geological survey and tunnel design are completed.

•07~11, 2008 : Construction of both near and far tunnels are completed.

•12, 2008 ~ 03, 2009 : Veto tanks and peripheral facilities (electricity, air circulation, drainage, network, etc.) are completed.

•10, 2008 : A mockup detector (~1/10 in volume) was built and is tested out.

•11, 2008 : SK new electronics were adopted and ready.

•Steel/acrylic containers and mechanical structures are under installation and will be completed until Nov. 2009.

•PMT installation is expected to start from Dec. 2009.

•Both near and far detectors are expected to be ready for data-taking in mid 2010.

Rock quality map

• Near detector site: - tunnel length : 110m

- overburden

height : 46.1m

• Far detector site: - tunnel length : 272m- overburden

height : 168.1m

(2007.3~2007.8)

Design of Tunnels

Experimental hall

Experimental hall

Win

g

tun

nel(L

)

Wing tunnel(C)

Detector

Win

g

tun

nel(C

)

Access tunnel

Access tunnel

Detectorvertical

hall

(2007.9~2007.11)

Near & far tunnels are completedby Daewoo Eng. Co. Korea(2008.6~2009.

3)

Detector vertical halls are ready(2008.12~2009.2

)

Buffer steel tanks are installedby NIVAK Co. Korea(2009.6~2009.9)

Acrylic vessels will be ready in Nov. 2009

by KOATECH Co. Korea

Target

Gam

ma c

atc

her

A half of target

Bending acrylic plates

(2009.7~2009.11)

Mockup Detector

Target + Gamma Catcher Acrylic Containers(PMMA: Polymethyl Methacrylate or Plexiglass)

Target Diameter

61 cm

Height 60 cm

Gamma

Catcher

Diameter

120 cm

Height 120 cm

Buffer Diameter

220 cm

Height 220 cm

Buffer Stainless Steel Tank

~1/10 of RENO in volume

Mockup Detector Assembly

Energy Calibration of Mockup Detector

137Cs

60Co

252Cf

137Cs

60Co

Electronics Use SK new electronics(all hardwares are ready)

Conceptual design of the system

Gd Loaded Liquid Scintillator

Recipe of Liquid Scintillator

Aromatic Solvent & Flour

WLS Gd-compound

LAB PPO +

Bis-MSB

0.1% Gd+TMHA

(trimethylhexanoic acid)

0.1% Gd compounds with CBX (Carboxylic acids; R-COOH)

- CBX : MVA (2-methylvaleric acid), TMHA (trimethylhexanoic acid)

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

• High Light Yield : not likely Mineral oil(MO)• replace MO and even Pseudocume(PC)• 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. (

이수화학 )

Raw/MCRaw/MCDataData

ProductionProductionModulesModules

ReconstructionReconstructionModulesModules

UserUserAnalysisAnalysisModulesModules

UserUserntuplesntuples

RACFrameWork

default modules data input and output, database access for run configuration and calibration

Has talk-to function for changing input parameters without recompiling

Addition of modules by user

Modules can be set as filter module for selecting events

Easy to use and build in RENO software environment

RRENO AAnalysisnalysis CControlontrol

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

RENO Event Display

Calculation of Background Rates due to RadioactivityConcentration

40K (ppb) Concentration

232Th (ppb) Concentration

238U (ppb) 40K [Hz] 232Th [Hz] 238U [Hz]

Total [Hz]

Rock 4.33(ppm) 7.58(ppm) 2.32(ppm) 1.06 7.14 0.99 9.2

LS in Target 0.010 0.018 0.014 9.00 1.63 3.67 14.3

Target Contatiner 0.008 0.207 0.168 0.08 0.24 0.63 1.0

LS in Gamma Catcher 0.010 0.018 0.014 15.18 2.27 5.27 22.7

Gamma Catcher Container

0.008 0.207 0.168 0.07 0.17 0.63 0.9

LS in Buffer 0.010 0.020 0.005 0.77 0.16 0.14 1.1

Buffer Tank 0.06 0.9 0.9 0.03 0.10 0.20 0.3

PMT 13.6 208.5 49.4 2.50 5.23 2.99 10.7

Total ~60.2

Systematic Uncertainty Goals

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 0.0

Neutron capture (H/Gd ratio) 1.0 < 0.1

Capture energy containment 0.4 0.1

Neutron geode distance 0.1 0.0

Neutron delay 0.4 0.1

Positron-neutron distance 0.3 0.0

Neutron multiplicity 0.5 0.05

combined 2.7 < 0.5

Expected Number of Neutrino Events at RENO

• 2.73 GW per reactor ⅹ 6 reactors• 1.21x1030 free protons per targets (16 tons)

• Near : 1,280/day, 468,000/year• Far : 114/day, 41,600/year

3 years of data taking with 70% efficiency

Near : 9.83x105 ≈ 106 (0.1% error) Far : 8.74x104 ≈ 105 (0.3% error)

RENO Expected Sensitivity90% CL Limits Discovery Potential” (3)

10x better sensitivity than current limit

New!! (full analysis)

RENO Expected Sensitivity

GLoBES group workshop@Heidelberg – Mention’s talk

SK m2

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

RENO is under installation phase.

Geological survey and design of access tunnels & detector cavities are completed → Civil construction was finished in February, 2009.

International collaborators are being invited.

Data –taking is expected to start in mid 2010.

Buffer steel containers are installed.