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Sun Kee Kim Seoul National University Underground Experiments in Korea ASK 2011 April 11-12, 2011, Seoul

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Underground Experiments in Korea. Sun Kee Kim Seoul National University. ASK 2011 April 11-12, 2011, Seoul. Questions on our Universe. What is the Universe made of? How big is the Universe? How did the Universe begin? What is the destiny of the Universe? - PowerPoint PPT Presentation

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Page 1: Sun  Kee  Kim Seoul National University

Sun Kee KimSeoul National University

Underground Experiments in Korea

ASK 2011April 11-12, 2011, Seoul

Page 2: Sun  Kee  Kim Seoul National University

Questions on our Universe

What is the Universe made of? How big is the Universe? How did the Universe begin? What is the destiny of the Universe? What is the meaning of life in the Universe? …

“The most incomprehensible thing about the world is that it is comprehensible”

- A. Einstein -

Some of these questions may be answered by understanding the nature of Dark matter and Neutrinos

Page 3: Sun  Kee  Kim Seoul National University

Quarks and leptons : Spin 1/2

tbcsdue e

,,,,,,,,,,

Gauge Bosons Spin 1 : gZW ,,,

Spin 2 : G

Higgs Bosons : Spin 0

AhhH ,,, 0

Standard Model of Elementary Particles

expected to be discovered at LHC

properties are not understood very well

Great achievement with partcile accelerators during the last century !

Page 4: Sun  Kee  Kim Seoul National University

Mostly Dark …

Composition of our Universe

006.0005.1 matter

Dark Energy73%

Dark Matter23%

Matter made of known particles 4%

Page 5: Sun  Kee  Kim Seoul National University

In 1933, Zwicky observed that the rotational speed of galaxies in a cluster of galaxies (Coma

cluster) too fast to be explained by mass of galaxies in the cluster

Existence of dark matter by astronomical observations

Gravitational lensing by cluster of galaxies

Collision of galaxy clusters

Rotation curves of galaxies

Cosmic Microwave BackgroundDensity of dark matter around the sun ~ 0.3 GeV /cm3

~ 5 x 10-

28 kg/cm3

Page 6: Sun  Kee  Kim Seoul National University

First idea of WIMP in 1977by B.W.Lee and S. Weinberg

Page 7: Sun  Kee  Kim Seoul National University

WIMP(Weakly Interacting Massive Particles)

Excellent CDM candidate

Relic abundancev

hA

13272 scm103

Annihilation cross section of a particle with a weak scale interaction

132522 scm10~)GeV100(~ vA

velocityrealtive : section, crossn annhilatio: ,7.0~//100

AMpcskmHh

LSP in SUSY

Page 8: Sun  Kee  Kim Seoul National University

Spin Dependent InteractionqqdL qaxial

55

2 2 232 ( 1)spin FG J J

1 ( )p p n na S a SJ

Spin Independent Interaction

qqaL qscalar 224 ( )scalar p nZf A Z f

2A

Elastic scattering of SUSY WIMP with ordinary nucleus

XLIIInd Rencontres de MORIOND Sun Kee Kim, Seoul National

University8

Page 9: Sun  Kee  Kim Seoul National University

rEE

R

RerE

RdEdR

0/

0

0

)χ~χ~( 01

01 NN

Elastic Sacttering of WIMP off a nuclues in the detector

Direct Search for WIMP

R : event rateR0: total event rateE0: most probable incident kinematic energyr : kinematic factor, 4MwMN/(MW+MN)2

• Recoil energy < 100 keV• Expected event rate

<1/kg/day or less

WIMP

Recoiled nucleus

Page 10: Sun  Kee  Kim Seoul National University

Status of WIMP search

vsun=232km/s sun

earth

vorbit=30km/s

=60o

2-6 keV

A=(0.0129±0.0016) cpd/kg/keV2/dof = 54.3/66 8.2 C.L.Fit :Acos[w(t-t0)]

DAMA Annual Modulation

Page 11: Sun  Kee  Kim Seoul National University

Neutrino mass and mixing

needs to be measured DayaBay, DCHOOZ, RENO

needs to be measured

measurable by neutrino oscillation

Page 12: Sun  Kee  Kim Seoul National University

Transition bb allowed

Forbidden b transition

Z

Energy

Z Z+1 Z+2

Qbb

100Mo

100Ru

100Tc

Neutrinoless Double Beta Decay

2022/1 ~0

bbbb MmT

0νββ decay occurs when mν≠0 and ν = ν

Page 13: Sun  Kee  Kim Seoul National University

Status of DBD searches

S13

100 meV

25 meV

2meVneed 1 ton detector

Positive signature?

Page 14: Sun  Kee  Kim Seoul National University

Challenges for Rare Processes

Dark Matter (Direct detection of WIMP)- Very weak interactions with ordinary matter : Rare- Very low energy signals- Large background - Nuclear recoil vs electron recoils

Neutrinoless Double Beta Decay Search - Life time is expected to be very long : Rare - Large background - 2νββ vs 0νββ Self background

These searches cannot be performed without an Underground Laboratorywithout an excellent detector

performance

Page 15: Sun  Kee  Kim Seoul National University

Cosmic ray 106eV ~ 1020eV, p, He,…

Nuclear interaction - secondary particles

1 muon /second/10 cm x 10 cm at sea level

Muon interaction creates neutrons

Neutron- mimic WIMP signal- generate radioactive isotopes

Neutrons from rocks can be avoided by a proper shielding

But, if muons interact within the shield, neutrons can enter the detector

Need to reduce the muon flux as much as possibleDeep underground experimental site

Why underground Laboratory ?

Page 16: Sun  Kee  Kim Seoul National University

Soudan MineCDMSCOUPP

Gran SassoDAMA, LIBRA

XENON, CRESST

CUORE, GERDA

Boulby Mine

NAIADZEPLINDRIFT

FrejusEDELWEISS

Super NEMO

SudburyPICASSO

KamiokaXMASS

YangyangKIMS

AMORE

Underground Laboratories

CanfraneANAISIGEX

SuchiwanULGeXenon

Page 17: Sun  Kee  Kim Seoul National University

Yangyang Underground Laboratory(Y2L)

Page 18: Sun  Kee  Kim Seoul National University

Korea Middleland Power Co.Yangyang Pumped Storage Power Plant

Yangyang Underground Laboratory

Minimum depth : 700 m / Access to the lab by car (~2km)

(Upper Dam)

(Lower Dam)

(Power Plant)

Construction of Lab. buildings done in 2003

Page 19: Sun  Kee  Kim Seoul National University

H.C.Bhang, J.H.Choi, S.C.Kim, S.K.KimJ.H.Lee, M.J.Lee, S.J.Lee, S.S.Myung

Seoul National University

U.G.Kang, Y.D.Kim, J.I. LeeSejong University

H.J.Kim, J.H.So, S.C.Yang Kyungpook National University

M.J.Hwang, Y.J.Kwon

Yonsei University

I.S.Hahn Ewha Womans University

Y.H.Kim, K.B.Lee, M. Lee Korea Research Institute of Standard

Sciences

J.LiInstitute of High Energy Physics

Y.Li, Q.Yue

Tsinghua University

KIMS(Korea Invisible Mass Search) collaboration

19

Page 20: Sun  Kee  Kim Seoul National University

KIMS research program

Dark Matter Search - CsI(Tl) crystal detector

An intermediate result was published (2007) 100 kg array running

Neutrinoless Double Beta Decay Search- Metal loaded liquid scintillator

- HPGe detector + CsI(Tl) crystal + Sn, Zn,.. to excited states, beta+ decays

- CaMoO4 crystal - scintillation technique - cryogenic technique

Page 21: Sun  Kee  Kim Seoul National University

Easy to get large mass with an affordable cost Good for AM study High light yield ~60,000/MeV Pulse shape discrimination Moderate background rejection Easy fabrication and handling Cs-133, I-127 (SI cross section ~ A2) Both Cs-133, I-127 are sensitive to SD interaction

WIMP search with CsI(Tl) Crystals

nuclear recoil

electron recoilIsotope J Abun <Sp> <Sn>

133Cs 7/2 100% -0.370 0.003127I 5/2 100% 0.309 0.075

73Ge 9/2 7.8% 0.03 0.38129Xe 1/2 26% 0.028 0.359131Xe 3/2 21% -0.009 -0.227

Page 22: Sun  Kee  Kim Seoul National University

KIMS(Korea Invisible Mass Search)

DM search experiment with CsI crystal CsI(Tl) Crystal 8x8x30 cm3 (8.7 kg)

3” PMT (9269QA) : Quartz window, RbCs photo cathode

~5 Photo-electron/keV

22

Page 23: Sun  Kee  Kim Seoul National University

WIMP search limit with 4 crystals

Nuclear recoil of 127I of DAMA signal region is ruled out unambiguiously

PRL 99, 091301 (2007)

Most stringent limit on SD(pure proton) interactions

Page 24: Sun  Kee  Kim Seoul National University

Data taking with 12 crystals12 crystals(104.4kg) running (from 2008) • Stable data taking for more than a

year• Unique experiment to test DAMA annual

modulation

CsI DAQ rate < 6 Hz

Sep. 2009 ~ Aug. 2010

24

Total exposure: 32793 kg days

Page 25: Sun  Kee  Kim Seoul National University

25

Relative intensity.....

Am calibration-> ~5 p.e /keV

Am-241 Energy Calibration

E(keV)

13.9keV Np L X-ray17.8keV Np Lb X-ray20.8keV Np L X-ray26.35keV gammaCs, I X –ray escape59.54 gamma

Page 26: Sun  Kee  Kim Seoul National University

26

High energy tail events rejection

Additional cut: Muon veto, file up rejection, trigger condition cut, multiple hit rejection

5us

Page 27: Sun  Kee  Kim Seoul National University

Modeling of Calibration data with asymmetric gaussian function

NR event rate estimation

• Fit the WIMP search DATA with PDF function from

gamma and neutron calibration data

extract NR events rate

n

Electron recoilNuclear recoil

Best fit

27

Page 28: Sun  Kee  Kim Seoul National University

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Surface alpha (SA) events background

222Rn progenies produce this background.

Page 29: Sun  Kee  Kim Seoul National University

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CsI(Tl) crystalsA: Rn progeny contaminated -exposed to Rn gas for one week

B: clean

Aluminum foil t=2um x 3 layers

A B

Sides are wrapped by teflon

Study of SA events with Rn progeny contaminated crystal

Tagged as Alpha at part B

BackgroundSurface alpha events

E(keV)

mean time(mt)

Page 30: Sun  Kee  Kim Seoul National University

30

The logrmt10 distribution for various types of particle

dttpulsedttpulsetrmt )(/)(10 in 10s

PSD parameter

SA

neutron

gammas

Page 31: Sun  Kee  Kim Seoul National University

31

Modeling WIMP search data with 3 components, SA, NR, gamma

det0

SANR(WIMP)gamma

3keV

10keV

4keV

5keV 6keV

7keV 8keV

9keV

Page 32: Sun  Kee  Kim Seoul National University

32

Determination of the 90 % C.L. limit of NR event rates

Pdf = f0 x FNR + f1 x FSA + (1-f0-f1) x Fgamma

The posterior pdf of f0 & f1 are obtainedfrom Bayesian analysis method.

Page 33: Sun  Kee  Kim Seoul National University

33

NR events rate for det0 to det12

Determined from Bayesian method

- 90% limit- 68% interval

3-11 keV

Counts/day/kg/keV

preliminary

Page 34: Sun  Kee  Kim Seoul National University

KIMS WIMP search

Spin Independent Spin Dependent

preliminary

Page 35: Sun  Kee  Kim Seoul National University

Sep. 2009 ~ Feb. 2011

Plan on Annual Modulation Stuudy

Taking data for more than 18 months 2 year data by this summer

~ 3 counts/day/kg/keV

Page 36: Sun  Kee  Kim Seoul National University

DBD Searches at KIMS

Passive targets : HPGe + CsI(Tl) [Nuclear Physics A 793 (2007)]

64Zn EC+b+ decay 124Sn bb to excited states of 124Te 122Sn EC+b+ decay

Active targets

124Sn 0νbb : Sn loaded Liquid scintillator [Astropart. Phys. 31,412 (2009)] 84Sr EC+b+ decay : SrCl2 crystal 92Mo EC+b+ decay : CanatMoO4 crystal 100Mo 0νbb decay : Ca100MoO4 crystal R&D effort is on going birth of AMORE

Page 37: Sun  Kee  Kim Seoul National University

β+EC decay of 92Mo511keV γ

511keV γ

Gamma detector

Active crystalwith 92Mo

Conceptual setup

• 92Mo nucleus is double EC and beta plus EC isotope

• EC/β+ Q-value=627keV, ECEC = 1,650keV• Abundance = 92Mo: 14.84%, 100Mo: 9.63%• e+ stops in active(CaMoO4) Crystal.

b/EC

37

Page 38: Sun  Kee  Kim Seoul National University

• PMTs & CsI crystals are crossly connected.• Lead shielding(10 cm)• CaMoO4 is surrounded by 14 CsI crystals

T1/2 > 2.3 x 1020y (90% CL)Paper in preparation

• U - CsI(Tl) crystals• Th - CsI(Tl) crystals• K – 1inch PMT• K – CsI(Tl) crystals• K – CaMoO4 crystal

38

β+EC decay of 92Mo

Page 39: Sun  Kee  Kim Seoul National University

New HPGe detector at Y2L

Will be used for - Measurement of internal background- DBD search with beta+

~527 cc~2.8kg

39

Co60/Cs137/Ba133

Energy Resolution

Page 40: Sun  Kee  Kim Seoul National University

CaMoO4 for ββ

resolutionCompton edge

CaMoO4 + LAAPD at -159oC

CaMoO4 DBD for Mo-100 (3034 keV), Ca-48(4272 keV)

high energy less background Mo-100 enrichment >90% not so difficult for Mo-100 search, Ca-48 need to be depleted Scintillator at room temp; 10-20% of CsI(Tl) at 20o increases at lower temp. Decay time ; 16 μ sec Wavelength; 450-650ns-> RbCs PMT or APD Can be used as cryogenic detector (absorber)

Z

Energy

Z Z+1 Z+2

Qbb

100Mo

100Ru

100Tc

Page 41: Sun  Kee  Kim Seoul National University

Mo-100 2β

Tl-208Bi-214

Signal (m=0.4eV)

Ca-48 2nββ

Ca-48 Depletion neededFirst 40Ca100MoO4 crystal

after big bang

S35

SB28CMO-3

D44 mmxL51mm~300g

40Ca100MoO4

Page 42: Sun  Kee  Kim Seoul National University

Advantages of using cryogenic calorimeters High energy resolution (ΔE/E < 1/1000) Ultra low energy threshold ( < 1 eV) Simultaneous readout of Charge or Light

discrimination of particle type (e, alpha, nuclear recoils)

Cryogenic Detector

e-h pair production : 3.6 eV in Si, 2.9 eV in Ge ( *kT (T=0.1K)~10 μeV) (BG 1.11 eV in Si, 0.67eV in Ge) 2/3 energy goes to phonons…

For nuclear recoil ~10% goes to ionization

1 keV energy deposit : ~ 60 photons (CsI(Tl)) , ~280 e-h pairs (Si)

Page 43: Sun  Kee  Kim Seoul National University

Cryogenic Detector

Absorber

Thermometer

Thermal link

Heat sink < 100 mK

, b, , etc.Energy absorption Heat (Temperature)

Choice of thermometers• Thermistors (doped Ge, Si)• TES (Transition Edge Sensor)• MMC (Metallic Magnetic Calorimeter )• STJ, KID etc.

Example

Page 44: Sun  Kee  Kim Seoul National University

Metallic Magnetic Calorimeter (MMC)

Magnetic material (Au:Er) in dc SQUID

junctions

Field coil

Au:Er(10~1000ppm)paramagnetic systemmetallic host: fast thermalization ( ~ 1ms) Can control heat capacity by magnetic field

g = 6.85 mT Δε = 1.5 eV1 keV 109 spin flips

U. of Heidelberg

Page 45: Sun  Kee  Kim Seoul National University

45

Experimental setup at KRISS with MMC

45

~ 500 m thick brass

base temperature : 13 ~ 100 mK

crystal size ~ 1 cm 0.7 cm 0.6 cm

Page 46: Sun  Kee  Kim Seoul National University

46

Performance of CMO+MMC

FWHM = 11.2 keV

42 keV

FWHM = 1.7 keV

Emission line of Mo : 18keV

Astroparticle Physics, 2011

5.5 MeV alpha

60keV gamma

high energy resolution suitable to search for Mo-100

0νββ

low energy thresholdsuitable to search for WIMP

Page 47: Sun  Kee  Kim Seoul National University

Cryogenic detector0.5% FWHM 15 keV

FWHM

Scintillation technique 5% FWHM resolution

CaMoO4 DBD Sensitivity

5 years, 100 kg 40Ca100MoO4 7.0x1026 years -> 20 – 70 meV

Page 48: Sun  Kee  Kim Seoul National University

Dark matter sensitivity of CaMoO4 cryogenic experiment

Bottino et al

Trotta et al

Ellis et al

CaMoO4 CDMS 2008 SuperCDMS 25kg

XENON10 2007 XENON100 6000 kgd

CMSSM, Ellis et al

CMSSM, Markov chain Trotta et al

Effective MSSM, Bottino et al

Eth=10 keV(5 and 100 kg year)

Eth=1 keV(5 and 100 kg year)

Page 49: Sun  Kee  Kim Seoul National University

AMoRE Collaboration Korea (39)

Seoul National University : H.Bhang, S.Choi, M.J.Kim, S.K.Kim, M.J.Lee, S.S.Myung, S.Olsen, Y. Sato, K.Tanida, S.C.Kim, J.Choi, S.J.Lee, J.H.Lee, J.K.Lee, H.Kang, H.K.Kang, Y.Oh, S.J.Kim, E.H.Kim, K.Tshoo, D.K.Kim, X.Li, J.Li, H.S.Lee (24)Sejong University : Y.D.Kim, E.-J.Jeon, K. Ma, J.I.Lee, W.Kang, J.Hwa (5)Kyungpook national University : H.J.Kim, J.So, Gul Rooh, Y.S.Hwang(4)KRISS : Y.H.Kim, M.K.Lee, H.S.Park, J.H.Kim, J.M.Lee, K.B.Lee (6)

Russia (16)ITEP(Institute for Theoretical and Experimental Physics) : V.Kornoukhov, P. Ploz, N.Khanbekov (3)

Baksan National Observatory : A.Ganggapshev, A.Gezhaev, V.Gurentsov, V.Kuzminov, V.Kazalov, O.Mineev, S.Panasenko, S.Ratkevich, A.Verensnikova, S.Yakimenko, N.Yershov, K.Efendiev, Y.Gabriljuk (13)

Ukraine(11)INR(Institute for Nuclear Research) : F.Danevich, V.Tretyak, V.Kobychev, A.Nikolaiko, D.Poda, R.Boiko, R.Podviianiuk, S.Nagorny, O.Polischuk, V.Kudovbenko, D.Chernyak(11)

China(3)Tsinghua University : J.Li, Y.Li, Q.Yue(3)

4 countries8 institutions

69 collaborators

49

Page 50: Sun  Kee  Kim Seoul National University

국가대형연구시설구축지도 (National Facility Road Map (NFRM))21 개 S 군에 선정됨 (NFRM 에는 282 제안 중 69 선정 , 69 개는 다시 S,A,B 군으로 분류 )

Page 51: Sun  Kee  Kim Seoul National University

SUMMARY

51

KIMS :Results using 3409 kg days data (PRL 99, 091301 (2007))

100 kg crystals installed in the shield and data taking is on going

PSD result shown today Annual modulation study in progress

DBD searches in various isotopes : Zn-64, Sn-124, Sn-122, Mo-92, Sr-84

Some best limits

Competitive DBD search using CaMoO4 crystals can be realized rather soon A new collaboration AMORE was formed

Page 52: Sun  Kee  Kim Seoul National University

Thank you

Page 53: Sun  Kee  Kim Seoul National University

Channeling

Orange: w/o channeling

Green: w/ channeling

When channeling is accounted, I recoil is preferred better chance for KIMSBut, because of Blocking, the effect of channeling might be smaller than DAMA Claimed

Na recoil

I recoil

Savage, Gelmini, Gondolo and Freese, arXiv 0808.3607

Well known technology to bend particle beam with crystal. Studied a lot in 1960s Quenching is expected to be less PSD may not work? Less studied for low energy ions.

Practically lower the trehsold

Page 54: Sun  Kee  Kim Seoul National University

Channeling

Understanding Quenching factorbetter is important.Plan to measure quenching factor and channeling effect using a neutron setupAlso simulation study is on going together

CsI(Tl) Q.F NaI(Tl) Q.F