Soo-Bong Kim

Dept. of Physics & Astronomy Seoul National University

April 15, 2009

A Korean Project of Neutrino Oscillations

Birth of NeutrinoBirth of Neutrino

Total spin is not conserved, either… 14C 14N + e–

spin 0 spin 1 spin 1/2

Bohr: Energy and momentum may not be conserved in decay ?…

F. A. Scott, Phys. Rev. 48, 391 (1935)Observed continuous spectra Predicted discrete spectra

14C decay

Physics in trouble with decay Energy & momentum are not conserved

Wolfgang Pauli’s introduction of an imaginary particle (1931)

Wolfgang Pauli’s introduction of an imaginary particle (1931)

Neutrino : Undetectable massless neutral fermion (Weakly interacting)

Neutrino

Neutrino: Elementary Particles

Elementary particles with almost no interactions

Almost massless: impossible to measure its mass

Universe full of neutrinos

Tiny Neutrino Masses

E=mc2

mass

10-27kg10-30kg10-36kg

SM

GUT

Mixing Angles

(12 , 23 , 13)

Unmeasured yet

Oscillating Neutrinos

Three flavors of neutrinos repeat transformation among them as time goes by.

Discovery of Neutrino Oscillations (1998)CKM Quark Mixing and CP Violation

Properties of Neutrinos

Almost no interaction with matter (via weak interaction only)

Mass is too small to measure

Elementary particles with three flavors (e, , )

Transformation among the three flavors

Universe full of neutrinos (330 per 1cm3)

Why is the neutrino physics so improtant?Why is the neutrino physics so improtant?

Neutrino Oscillation and Mass Window for New Physics !

Origin of Our Universe !!

Neutrinos are hot !

1

2

Neutrino OscillationNeutrino Oscillation

1 2

m1 m2

Flavor states Mass states

• neutrino oscillations due to wave property of neutrino

1 1

2 2

cos sin

sin cos

m

m

im t p im t pt e e 2 21 2/ 4 / 4

1 2| , | cos ( ) | s in ( )

2

1

2-Neu

trin

o Osc

illat

ion

2-Neu

trin

o Osc

illat

ion

Oscillation Probability Oscillation Probability

Neutrino energy

Neutrino trajectory

Solar Neutrino(e) OscillationsSolar Neutrino(e) Oscillations

Nuclear fusion : 4p → 4He + 2e+ + 2e + thermal energy

Deficit of solar neutrinos → Evidence for oscillations

- Homestake (Cℓ, 1968~1993): first measurement

- Kamiokande (H2O, 1986~1993): energy/directionality

- SAGE & GALLEX/GNO (Ga, 1990~2001)

- Super-Kamiokande (H2O, 1996~ ): precision exp.

Discovery of Solar Neutrino Oscillations

- SNO (D2O, 2002): detect / (e → & )

Confirmation of Solar Neutrino Oscillations

- KamLAND (2002): reactor neutrino oscillation

12 측정 )

Atmospheric Neutrino() OscillationsAtmospheric Neutrino() Oscillations

Cosmic ray (p, He, …) + Atmosphere → /K meson → → e +

Discovery of atmospheric neutrino oscillations ( → )

- Super-Kamiokande (1998)

- measurement of 23

Confirmation of atmospheric neutrino oscillations

- K2K (2004) : accelerator beam (250km)

- MINOS CNGS (2006) : ~700km

23 측정 )

Summary of Neutrino Oscillation Parameters

23

12

13

m12

2 = 7.9(5% )10-5 eV2

m23

2 = 2.4(13% )10-3 eV2 ≈ m132 mass difference :

sin212

= 0.31(9%)

sin223

= 0.44(+20–11% )

sin213

< 0.17 (90% C.L.) mixing angles :

Precision Measurementof Neutrino Oscillation Parameters

Ue3

(New field of particle physics open!)

U Ue1 Ue2 Ue 3

U1 U2 U 3

U1 U 2 U 3

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

0reactor and accelerator

13 = ?

atmospheric SK, K2K

23 = ~ 45°Large and maximal mixing!

(atmospheric neutrinos & neutrino beams)

SNO, solar SK, KamLAND

12 ~ 32°

(Solar neutrinos& reactor neutrinos)

?

CP : CP phase

13 from Reactor and Accelerator Experiments

Pee 1 sin2 213 sin2 m312L

4E

cos4 13 sin2 212 sin2 m21

2L

4E

- Clean measurement of 13

- No matter effects

CP violation

mass hierarchy

matter

* Reactor

* Accelerator

- sin2213 is a missing key parameter for any measurement of CP

Nuclear Power Plants

Reactor Neutrinos

영광

울진

Reactor Neutrinos

인체에 유해한 방사능 ( 중성자 , 알파선 , 베타선 , 감마선 ) 은 원자로 내부에서 차폐됨

핵붕괴시 방출되는 중성미자는 물질과 거의 반응을 하지 않으므로 인체에 무해하며 원자로를 빠져 나와서 사방으로 끊임없이 퍼져 나감 ( 매초당 ~1017/m2 방출 ) 영광발전소는 열생산 최대용량이

17GW 로서 세계 2 위의 강력한 중성미자 방출원임

Energy Spectra of Reactor NeutrinosEnergy Spectra of Reactor Neutrinos

Detection Method of Reactor Neutrinos(Reines & Cowan, 1957)

(2) 5<Edelayed <11MeV

n capture energy

Detection of Reactor Neutrinos

p

νe

e+

e-

γ(0.511MeV)

γ(0.511MeV)

n

Gd

γ

γ γ

γ

E ~ 8MeV

30μs

prompt signal

Delayed signal(1) 0.7<Eprompot <9MeV

e+ energy

Chooz: 13<130

RENO (13 )

KamLAND (12)

Reactor Neutrino ExperimentsReactor Neutrino Experiments

New Reactor Neutrino Experiment (13)

Need identical detectors to reduce the systematic errors in 1% level

Detectors should be at underground to reduce the cosmic-ray backgrounds

Find disappearance of e fluxes due to neutrino oscillation as a function of energy using multiple, identical detectors

Oscillation Parameters from Reactor Neutrinos

0

0.2

0.4

0.6

0.8

1

1.2

0.1 1 10 100 1000

L(km)

P(νe

->

νe)

sin2 13=0.1

L~50km: accurate sin2212

sin2213=0.1, E=4MeV

P e e 1 sin2 213sin2 m132 L

4E

P e e 1 sin2 212sin2 m122 L

4E

L~1.5km: pure sin2213 L~5km: m213

Scope of RENO Project

L~180kmKamLAND:accurate m2

12

moderate 12

3RENO

)1%(4.2~sin

sin

122

122

Reduction of Reactor Neutrinos due to Oscillations

sin2213 > 0.01 with 10 t• 14GW• 3yr ~ 400 t•GW•yr (400 t•GW•yr: a 10(40) ton far detector and a 14(3.5) GW reactor in 3 years)

Dis

app

eara

nce

Reactor neutrino disappearance Prob. due to 13 with the allowed 2 range in m23

2

Double-CHOOZ (France)

* Proposal (June 20, 2006) : hep-ex/0606025

Double-Chooz Collaboration: France, US, Germany, Italy, Japan, England, Brasil, Spain & Russia

* 2010 년 근거리 /원거리검출기 동시 가동

Daya Bay (China)

* Proposal to DOE (Jan. 15, 2007): hep-ex/0701029

Daya Bay Collaboration: China, US, Czech Republic, Hong Kong, Russia & Taiwan

Experiment Location

Thermal

Power

(GW)

Detector Locations

Near/Far

(m)

Depth

Near/Far

(mwe)

Target

Near/Far

(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

World Competition in the Reactor Neutrino Experiments

Chonnam National University Dongshin University Gyeongsang National University Kyungpook National University Pusan National University Sejong University Seoul National University Sungkyunkwan University Institute of Nuclear Research RAS (Russia) Institute of Physical Chemistry and Electrochemistry RAS (Russia)

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

RENO Collaboration

RENO Experimental Setup

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

Schedule for RENO Construction

Activities

Detector Design& Specification

Geological Survey& Tunnel Design

DetectorConstruction

DetectorCommissioning

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

Detector construction

Tunnel excavation

Rock sampling (DaeWoo Engineering Co.)

Rock samples from boring

Rock quality map

• Near detector site: - tunnel length : 110m

- overburden

height : 46.1m

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

height : 168.1m

Stress analysis for tunnel design

Mixing & Supplying Liquid Scintillators

Data Acquisition System

Mockup Detector Event Display

Real time display: Online monitoring tool

Basic information on histograms

PMT hit display

RENO Detector Design and Specification

RENO Detector

Structure design completed (’08. 12)

PMT test completed & under purchase

Use SK new electronics

광센서의 신호를 초고속 처리하는 ASIC을 사용한 데이터 수집 장비

DAQ Electronics completed (’08. 11)

Mixing for Liquid Scintillator :

Aromatic Solvent

Flour WLS Gd-compound

LAB PPO, BPO

Bis-MSB, POPOP

0.1% Gd+TMHA

(trimethylhexanoic acid)

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

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

R&D of Gd Loaded Liquid Scintillator

LAB(Linear Alkyl Benzene) Properties :

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

PC100% LAB100% PC40% PC20% LAB100% PC20% N2 LAB60% LAB80% MO80%

Synthesis of Gd-carboxylateprecipitation

Rinse with 18MΩ water

Dryer

R&D with LAB

Light yield measurement

PC100% LAB100% PC40% PC20% LAB100% PC20% N2 LAB60% LAB80% MO80%

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

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

PC 와 Mineral oil/Dodecane 대용으로 사용할 수 있는 LAB(Linear Alkylbenzene) 의 분자 구조식

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

Raw/MCRaw/MCDataData

ProductionProductionModulesModules

ReconstructionReconstructionModulesModules

UserUserAnalysisAnalysisModulesModules

UserUserntuplesntuples

RACFrameWork

default modules data input and output, database access for run configuration and calibrationHas talk-to function for changing input parameters without recompilingAddition of modules by userModules can be set as filter module for selecting eventsEasy to use and build in RENO software environment

RRENO AAnalysisnalysis CControlontrol

Inverse Beta DecayInverse Beta Decay

Cosmic MuonCosmic Muon

RENO Event Display

target

buffer

-catcher

Reconstruction of Cosmic Muons

~140cm

~40cm

~120cm

A

B

C

D

Veto(OD)

Buffer(ID)

pulse height timeOD PMTs

ID PMTs

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+

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 9.19

LS in Target 0.001 0.001 0.001 0.90 0.09 0.26 1.25

Target Contatiner 0.008 0.05 0.008 0.08 0.06 0.03 0.17

LS in Gamma Catcher 0.001 0.001 0.001 1.52 0.13 0.38 2.03

Gamma Catcher Container

0.008 0.05 0.008 0.07 0.04 0.03 0.14

LS in Buffer 0.001 0.001 0.001 0.08 ~ 0 0.03 0.11

Buffer Tank 0.06 0.9 0.9 0.03 0.10 0.20 0.33

PMT 13.6 208.5 49.4 2.50 5.23 2.99 10.72

Total ~24

Systematic ErrorsSystematic Source CHOOZ (%) RENO (%)

Reactor related absolute

normalization

Reactor antineutrino flux and cross section

1.9 < 0.1

Reactor power 0.7 < 0.1

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 0.2

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 < 0.6

RENO Expected Sensitivity

10x better sensitivity than current limit

New!! (full analysis)

GLoBES group workshop@Heidelberg – Mention’s talk

SK m2