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