XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
XXIV SEMINARIO NAZIONALE di FISICA NUCLEARE E SUBNUCLEARE
OTRANTO, Serra degli Alimini, 21-27 Settembre 2012
Argomento: Studio del decadimento doppio beta ai LNGS
Lezione 2: Esperimento LUCIFER
OTRANTO
21-27 Settembre 2012
Double beta decay study at LNGS
(the experiment LUCIFER)
I. Dafinei
Università "La Sapienza" di Roma and Sezione INFN - Roma
Lucifer
made in the frame of LUCIFER experiment
FP7/2007-2013
ERC grant agreement n. 247115.
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Outline
• scintillating bolometers
• LUCIFER experiment
• large scale crystal production issue
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
scintillating bolometers, why?
•device able to measure both phonon
(heat) excitation and the photon
(scintillation) excitation generated in a
crystal by a nuclear event
• for a given energy deposit, the
amount of emitted light is
different for α wrt β/γ
• scatter plot light vs. heat
separates α from β/γ
beta
Original idea
Milano group
mid 1990’s
CaF2 scintillating
bolometer
The experimental basis for LUCIFER is the R&D
activity lead by Stefano Pirro at LNGS ,
alpha
in the framework of the programs:
•
•
Dafinei_Otranto2012_Lesson-2
BOLUX, funded by INFN – CSN5
ILIAS-IDEA funded by the EC (WP2-P2)
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
scintillating bolometers, how?
(contains the 0νDBD candidate)
T0  10mK
C  2nJ / K  1MeV / 0.1mK
dR
 20k / keV
dE
 T 

C (T )  
 D 
T ( t ) 
3
E  t
e
C
Dafinei_Otranto2012_Lesson-2
• material purity
– radioactive contamination (<ppt)
– chemical purity (<ppm)
• fabrication constraints
– crystal growth, mechanical processing
– package and transport
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
light detector (LD) performances
LD: Ge disks (0.3 to 1 mm thickness)
performances of a LD usually
evaluated through the Energy
resolution on the 55Fe doublet (5.9 &
6.5 keV X-Ray)
Ge (Ø = 35 mm)
FWHM=250 eV
S. Pirro et al., "Development of bolometric light detectors for double beta decay searches", NIM A 559 (2006) 361–363
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
first scintillating bolometer
(March 2004)
made of a 1 cm3 PbMoO4 crystal glued on a copper frame
and facing a 36 mm diam Ge Crystal, acting a Light Detector
Light detector
thermistor
Dafinei_Otranto2012_Lesson-2
heater
reflecting
cavity
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
first scintillating bolometer
S. Pirro – Cryoscint conference - Oxford, 7 Dec 2004
even if on a small sample this was the first proof
of alpha discrimination on a Mo based compound
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
more on background measurement
3x3x6 cm3, 420 g CdWO4
Optical Materials 31 (2009) 1388
44 days background
2615 keV 208Tl 
The MC simulation predicts a background level of 10-4 c/keV/kg/y in the region of interest
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
scintillating bolometers
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
more on discrimination power
C. Arnaboldi et al., "CdWO4 scintillating bolometer for Double Beta Decay: Light and heat
anticorrelation, light yield and quenching factors ", Astroparticle Physics, 34 (2010), pp. 143-150
excellent discrimination
CdWO4
β/

first exhaustive explanation of the anticorrelation (bent lines)
between heat and light release in a scintillating bolometer
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
LUCIFER Low-background Underground Cryogenics Installation For Elusive Rates
Principal Investigator: Fernando Ferroni
ERC-2009-AdG 247115
isotope:
material:
82Se
, 100Mo , 116Cd
ZnSe , ZnMoO4 , CdWO4
technique:
scintillating bolmeter
LUCIFER timeline
2012
2013
2014
2015
R&D on light detectors
Thermistor production
Natural crystal (growth) R&D
15 kg 82Se production
Enriched crystal growth
Detector assembling
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
LUCIFER in a glance
•array of 36÷44 enriched (95%) Zn82Se crystals
•total 82Se nuclei: (7.1÷8.9) 1025
•expected background in the ROI (2995 keV): (3÷6)10-3 c/keV/kg/y
•energy resolution of the single detector expected: 10 keV FWHM
•location: CUORICINO (now CUORE-0) cryostat (till 2015)
Bolometric Light Detector
Ge crystal
Zn82Se crystal
(Ø=45mm, h= 55 mm)
W=483 g
Reflecting Foil
PTFE supports
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
LUCIFER hints
The -induced background is recognized through two independent measurements: 1) the decay time of the scintillating signal
2) the different scintillation yield between  and / particles (the “usual” light Vs Heat scatter plot)
ZnSe crystals shows an “inverse” QF, i.e. -particles scintillate more than /’s
(Astrop. Phys. 34 (2011) 344-353 )
1) Decay time of the scintillation light
2) Light Vs Heat scatter Plot
/ scintillation
“Ionization coincidences” between
Ge light detector and ZnSe
-scintilaltion
Direct ionization
12.5 days
measurement
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
LUCIFER hints
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
alpha discrimination > 20 sigma !
without light detection
ZnMoO4
radio-clean!
J.W. Beeman et al., "ZnMoO4: A promising bolometer for neutrinoless double beta …",
Astroparticle Physics 35 (2012) 813–820
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
LUCIFER hints
Energy resolution compatible with CUORE detectors
-Discrimination without light detection at 14 sigma

Shape thermal pulse
OTRANTO
21-27 Settembre 2012
arXiv:1207.0433v11
ZnMoO4
Dafinei_Otranto2012_Lesson-2
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
Radiopurity already at top level, no evidence
of 232Th contamination <1.4x10-12 g/g
β/
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
LUCIFER hints
cryogenic “force”
Two above–ground (Milano Bicocca) + THREE deep underground (LNGS)
Hall C cryostat
Cuore-0/Lucifer cryostat
Dafinei_Otranto2012_Lesson-2
New Cryostat for Scintillating Bolometer (Oct 2012)
Ioan Dafinei
INFN Sezione di Roma, ITALY
LUCIFER experiment
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
LUCIFER hints
radio-purity check
1) High Purity GErmanium – HPGE (,) LNGS
2) Surface Barrier Detectors – SBD () LNGS/MIB
Direct measurement of radioactivity.
The most sensitive HPGE worldwide
3) Neutron Activation Analysis – NAA PAVIA LENA/MiB
4) Inductive Coupled Plasma Mass Spectroscopy - ICPMS
Measurement of concentration
of specific nuclei (238U 232Th)
2 ICPMS – HR (10-14 g/g) LNGS + MIB
For DBD scintillating bolometers
Dafinei_Otranto2012_Lesson-2
ICPMS –HR (10-12 g/g)
LNGS
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
~1ton
TeO2
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
~80tons
PbWO4
~1ton
TeO2
Compact Muon Solenoid
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
High Energy Physics (HEP)
EM calorimetry
effectiveness
PM spectral
&
sensitivity
emission
spectrum
radiation
length
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Rare Events Physics (REP)
• extremely high sensitivity
• very low background
Molière radius
Light Yield (LY)
m
response
time
Tt
Zeff
afterglow
hygroscopic
Hardness
(Moh)
Radiaton
hardness
n
r
main technological constraints
crystal perfection
radio-purity
bigger challenge: quantity (in HEP) is exceeded by difficulty (in REP)
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
CUORE case
only 2-3% crystals
can be measured
dedicated TeO2 synthesis facility
@ Kunshan Chemical Plant
dedicated production protocols
-environment conditions
-equipment and infrastructures
-materials handling
Dafinei_Otranto2012_Lesson-2
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
precautionary principle: raw materials, reagents,
intermediary products, processes and procedures
dedicated crystal growth
facility @ SICCAS Jiading
dedicated clean room
SICCAS/INFN @ Jiading
dedicated measurement protocols
-dimensions
-crystal perfection
-radio-purity
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
• question:
– is it feasible a similar enterprise in
the case of scintillating bolometers?
• answer:
– TeO2 crystal was a lucky case:
• industrial scale production already existed
• easy implementation of improvements imposed by
DBD application
• long term existing market for high quality crystals
– scintillating crystals for DBD is a
more complex case:
• no scintillating material for DBD use was produced
at large scale till now
• some of the problems to be addressed were solved
in the case of TeO2 crystal production
• work still needed for a reliable production
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
Dafinei_Otranto2012_Lesson-2
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
8
enriched Se elemental
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
URENCO, Stable Isotopes Division
SeF6 conversion to Se through
a dedicated procedure to meet
DBD application requirements
10-10 instead of
<10-12
preferred!
ZnSe synthesis and crystal
growth may work as purifiers
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
ZnSe crystal growth
recovery
and
recycling
SmiLab (ISMA Kharkov expertise)
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
ZnSe crystal
growth
mechanical
processing
ZnSe samples for cryogenic test
sample
Φ[mm]
H [mm]
237-7
48.2
49.1
173-6
48.0
51.6
174-6
46.7
50.8
97-2
47.9
52.0
ZnSe:Sr
23.6
22.8
-different thermal treatment during
crystal growth
-chosen from a set of 11
-cryogenic test to fix the best growth
conditions for maximal light output
and bolometric performance
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
large scale crystal production issue
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
ZnSe crystal growth
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
acknowledgements
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
this work was made in the frame of
LUCIFER experiment funded by the European
Research Council under the European Unions
Seventh Framework Programme
FP7/2007-2013 / ERC
grant agreement n. 247115.
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
recommended bibliography
OTRANTO
21-27 Settembre 2012
(.pdf files available upon request)
1.
N. Nosengo, "Lead from ancient shipwreck will line Italian neutrino experiment",Nature (News) 15 April2010,
http://www.nature.com/news/2010/100415/full/news.2010.186.html
2.
A. Alessandrello et al., "Measurement of radioactivity of ancient roman lead ...", NIM B61 (1991) 106-117
3.
C. Arpesella, "A Low Background Counting Facility at Laboratori Nazionali del Gran Sasso ", Appl. Radiat. Isot. Vol.47,
No.9/10, pp. 991-996 (1996)
4.
P.Belli et al., "Deep underground Neutron Flux Measurement with Large BF3 Counters", Il Nuovo Cimento vol. 101 A, no. 6,
Giugno 1989
5.
Ahlen S. P. et al., “Study of penetrating cosmic ray muons and search for large scale anisotropics at the Gran Sasso Laboratory”,
Phys. Lett. B, Vol. 249, no.1 (1990), pp.149-156
6.
L. Cardani et al., “Performance of a large TeO2 crystal … “, JINST 7 P01020 (2012)
7.
S. Pirro et al., "Development of bolometric light detectors for double beta decay searches", NIM A 559 (2006) 361–363
8.
L. Gironi etal., "CdWO4 bolometers for double beta decay search", Optical Materials, Vol. 31, Issue 10, Aug. 2009, pp. 1388-1392
9.
C. Arnaboldi et al., "CdWO4 scintillating bolometer for Double Beta Decay: Light and heat anticorrelation, light yield and
quenching factors ", Astroparticle Physics, Volume 34, Issue 3, October 2010, Pages 143-150
10.
J.W. Beeman et al., "ZnMoO4: A promising bolometer for neutrinoless double beta …", Astroparticle Physics 35 (2012) 813–820
Dafinei_Otranto2012_Lesson-2
Ioan Dafinei
INFN Sezione di Roma, ITALY