the amore project to search for 0 of 100 mo using low temperature detectors yong-hamb kim (...

The AMoRE Projectto search for 0 of 100Mo

using low temperature detectors

Yong-Hamb Kim ( 김용함 )

- Center for Underground Physics, IBS

- KRISS

Joint Winter Conference on Particle Physics, String and Cosmology

YongPyong-High1 2015

2YongPyong-High1 2015

The AMoRE Project

to search for neutrinoless double decay of 100Mo using cryogenic 40Ca100MoO4 detectors

AMORE: ‘Love’ in Italian

AMORE: “A cosmetic company in Korea

AMoRE: Advanced Mo-based Rare process Experiment

Ø4cmx4cm CaMoO4 crystal

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AMoRE collaborationInstitute for Basic Science, Daejeon, Korea

Korea Research Institute of Standards and Science, Daejeon, Korea

KyungPook National University, Daegu, Korea

Sejong University, Seoul, Korea Seoul National University, Seoul, Korea

Ewha Womans University, Seoul, Korea Chung-Ang University,

Semyung University, Korea

Soongsil University, Korea

Institute for Theoretical and Experimental Physics, Moscow, Russia

JSC Fomos-Materials, Moscow, Russia

Baksan National Observatory, Kabardino-Balkarskaya Republic, Russia

Institute for Nuclear Research, Kyiv, Ukraine

Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany

Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

Tsinghua University, Beijing, China Nakhon Rajabhat University, Thailand

Abdul Wali Khan University, Pakistan

Institut Teknologi Bandung (ITB), Indonesia

7 counties, 16 institutions, 90 collaborators

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Double beta decay

Double Beta Decay with two neutrinos

2νββ proposed by Maria Geoppert-

Mayer in 1935.

First observed directly in 1987.

Why 50 years?

T1/2(2νββ) : 1019 ~ 1021 y

Background T1/2(U, Th) : 1010 y

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Neutrinoless double beta decay (0νββ)

Double Beta Decay with two neutrinos

Double Beta Decay with no neutrino

requires massive Majorana ν !

Key test proposed by Racah in 1937

It may answer

- Mass of neutrinos ( )

- Majorana ( ), or Dirac particles ( )

- Lepton number conservation

202/11 mT

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Eb

MT

A

aNT a

)2(ln(exp)02/1

Experimental Sensitivity of T1/2 (0)

DBU: counts/ (keV kg year)

IsotopicAbundance

Atomicmass Background level

(count/keV kg year)

EnergyResolution

Time

Detector MassDetectionEfficiency

For “zero” background case;# of background events ~ 0 (1)

For sizeable background case;

AMoRE10kg

AMoRE200kg

CLa n

MT

A

aNT )2(ln(exp)0

2/1

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100Mo is chosen for 0 experiment

100Mo High Q-value () of 3034.40 (12) keV. High natural abundance of 9.7% Relatively short half life (0) expected from theoretical

calculation

Candidate Q (MeV) Abund. (%)

48Ca 4.271 0.1976Ge 2.040 7.882Se 2.995 8.7

100Mo 3.034 9.7116Cd 2.802 7.5124Sn 2.228 5.8130Te 2.533 34.1136Xe 2.479 8.9150Nd 3.367 5.6

21 20

1/2 0 0e

mT G M

m

Barea et al., Phy. Rev. Lett. 109, 042501 (2012)

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AMoRE detector technology

CaMoO4

- Scintillating crystal - High Debye temperature: TD = 438 K, C ~ (T/TD)3

- 48Ca, 100Mo 0ν candidates - AMoRE uses 40Ca100MoO4 w. enriched 100Mo and depleted 48Ca

40Ca100MoO4 + MMC

MMC (Metallic Magnetic Calorimeter) - Magnetic temperature sensor (Au:Er) + SQUID - Sensitive low temperature detector with highest reso-lution - Wide operating temperature - Relatively fast signals - Adjustable parameters in design and operation stages

CaMoO4

Light sensorMMC

MMC phonon sensor

<10-50 mK>

Low Temp. DetectorSource = Detector

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CaMoO4 crystal development

12.5 cm

2.2 cm

2.2

cm

Korea(2003) Ukraine-CARAT(2006) Russia(2006)

30x30x200mm

IEEE/TNS 2008

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Temperature dependent scintillation

CaMoO4 absolute light yield @RT: 4900590 ph/MeV (H.J. Kim et al., IEEE TNS 57 (2010) 1475)

Light yield at low temp. : ~ 30,000 ph/MeV Largest light yield among Mo contained crystals.

From RT to 7 K, the light yield increases 6 times (V.B. Mikhailik et al., NIMA 583 (2007) 350)

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100Mo, 40Ca enriched materials

Mo-100 isotope production:ECP (Electrochemical plant) RussiaURENCO Netherland

100MoO3 - Enrichment: 100Mo = 97%

- Impurities ICP-MS measurement: U 0.2 ppb, Th 0.1 ppb

HPGe At Baksan: 226Ra < 2.3 mBq/kg, 228Ac < 3.8 mBq/kg

Ca-40 isotope production:

ELEKTROCHIMPRIBOR, Lesnoy, Russia40CaCO3

- 48Ca < 0.001%

- Impurities: U ≤ 0.1 ppb, Th ≤ 0.1 ppb, Sr = 1 ppm, Ba = 1 ppm 226Ra = 51 mBq/kg 228Ac(228Th) = 1 mBq/kg

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40Ca100MoO4 crystals

• SB28

weight 196 g

• SB29

weight 390 g

• S35

weight ~300 g

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4p gamma veto system

Internal backgrounds of 40Ca100MoO4 crystals

-b a decay in 238U 214Bi (Q-value : 3.27-MeV) → 214Po (Q-value : 7.83-MeV)→ 210Pb

-a a decay in 232Th 220Rn (Q-value : 6.41-MeV) → 216Po (Q-value : 6.91-MeV)→ 212Pb

214Po : 1.93-MeV, 2445 events, 1.74mBq/kg

216Po : 1.62-MeV, 363 events, 0.26mBq/kg

220Rn : 1.44-MeV

210Po : 1.13-MeV

214Bi

216Po : 1.61-MeV, 57 events, 0.07mBq/kg

214Po : 1.93-MeV, 63 events, 0.08mBq/kg

Crystal S35 Crystal SB28

4p CsI(Tl) active setup with Pb shielding at Y2L

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Solid State Detectors

Measurement methods

Charge, Light, Phonon(Temperature)

Thermometer

Charge collector

Semiconductor

Light detector

Thermometer

Scintillator

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Measurement Chains in LTDs

Events

Phonon

Light

Charge

CRESST, RuciferAMoRE, LUMINEU

CDMS, EDELWEISSCUORE

examples

Advantages of using LTDs for rare event search• Low threshold & High resolution• Active background rejection

Charge, Light, Phonon(Temperature)

Low temperature favorable

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Low temperature detectors (Calorimeters)

Absorber

Thermometer

Thermal link

Heat sink < 1 K

Energy absorption Temperature

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

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Metallic Magnetic Calorimeter (MMC)

Magnetic material Au:Er(100~1000ppm)• weakly-interacting paramagnetic system• metallic host: fast thermalization ( ~ 1ms)

g = 6.8

5 mT Δε = 1.5 eV

1 keV 109 spin flips

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Highest resolution detector

1.6 eV FWHM for 6 keV x-rays

<2013 Heidelberg Univ.>

<2013 KRISS>

0.4keV FWHM for 60keV

1.2keV FWHM Gaussian width for 5.5MeV

Am241 full spectrum MMC with gold foil absorber

with C ~ 0.3kg CaMoO4

<2013 KRISS>

Gold foil absorber

MMC chip

Au:Er

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Phonon sensor for AMoRE

Gold film

We measure both thermal and athermal phonons.

Phonon collectorPatterned gold film

Gold wires(thermal connection)

MMC

rise-time: ~ 0.5ms

<Heat flow optimization>

216 g CaMoO4

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Photon sensor with MMC

MMC chip

SQUID sensor

Thermal connection

Phonon collector(Gold films)

Light absorber(Ge wafer)

Wafer holder(Cu, heat bath)

rise-time: ~ 0.2 msTemperature inde-

pendent rise-time !

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Detector Assembly

Light detector 2 inch Ge wafer + MMC196 g 40Ca100MoO4

(doubly enriched crystal)

Phonon collector film on bottom surface

Present detector being used in an over-ground lab (KRISS)

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Alpha and electron events

PSD Light/Heat ratio

Clear separation in PSD and Light/Heat ratios!

AMoRE@over-ground

- Result summary -

AMoRE@over-ground

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Pulse Shape Discrimination (phonon only)

AMoRE@over-ground

17.5 separation

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Light/Heat ratios AMoRE@over-ground

8.6 separation

CaMoO4

Ge

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Energy spectrum

Energy (keV) 511 1461 2615

FWHM (keV) 4.3 5.7 8.7

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YangYang Pumped Storage Power Plant

YangYang(Y2L) Underground Laboratory

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

(Upper Dam)

(Lower Dam)

(Power Plant)

KIMS (Dark Matter Search)

AMoRE (Double Beta Decay Experiment)

Seoul

Y2L

700m

1000m

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Lab space in Y2L

Some more lab space has been made at an unused tunnel

KIMS (CsI) Lab. ~ 100m2

New Lab. Space ~ 1000 m2

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Low Temperature LAB in Y2L

Dec. 2014Jan. 2015

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Summary of the AMoRE project

• Crystal: 40Ca100MoO4 , doubly enriched scintillating crystals

• MMC technology for heat and light measurement• Temperature: ~20 mK• Zero background measurement in ROI• Location: Y2L (till Phase I) and a new lab (after)• Fully funded for Pilot, Phase I and II.

  Pilot Phase I Phase II

Mass 1 kg 10 kg 200 kg

Sensitivity(mee) (meV) 300-900 60-180 10-30

Location Y2L Y2L New Lab

Schedule 2015 2016 2019

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Scheduled AMoRE experiment

<AMoRE Pilot, 2015><AMoRE10, 2016>

<AMoRE200, 2019>

Each Cell : D=70 mm, H=80 mm. CMO (D=50mm, H=60mm, 506g)

30 layers(2.4 m height)-13 columns or 20 layers(1.6 m height)-19 columns

CMO: ~ 300g 5 layers-7 columns

5 CMOs: ~ 1 kg

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AMoRE Sensitivity & Competitiveness

AMoRE 10

AMoRE 200

Eff

ecti

ve N

eutr

ino

mas

s (

eV)

Lightest neutrino mass (eV)

Tow

ard lower neutrino m

ass

Now

AMoRE Pilot

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We need larger spaceDeeper place?

Mt. Daeduk

IBS

Mt. Jang

Mt. Duta

Y2L

Myungji

Hwaak

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SARF(Samcheok Astro-particle Research Facility)

A proposal for new underground lab for future projects

N

S 1400m

길이 : 3.7km , 경사도 : ~8%

Lab space

Accesstunnel

Entrance

미로면삼거리 구룡골

Area :2000m2

해발 180 m

15m

40m20m

80m

미로면 고천리 대방골

Mt. Duta

34YongPyong-High1 2015

감사합니다