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 1: Il decadimento doppio beta senza neutrini
OTRANTO
21-27 Settembre 2012
Neutrinoless Double Beta Decay
Experiments
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-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Outline
• neutrino mass, theoretical and experimental challenges
• neutrinoless DBD importance for neutrino physics
• experimental methods for DBD study, particularities
of neutrinoless DBD
• the cryogenic bolometer, ideal tool for DBD study
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
introduction
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Nach dem Vorschlag von W. Pauli kann man z.B. annehmen,
das beim β-Zerfall nicht nur ein Elektron, sondern auch ein
neues Teilchen, das sogenannte "Neutrino" (Masse von der
Grossenordnung oder kleiner als die Elektronenmasse; keine
elektrische Ladung) emittiert wird. E. Fermi, Z. Physik 88, 161 (1934)
… so what?
neutrino has
a mass!
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
introduction
Seventh Solvay Conference on Physics, Brussels 1933
Dafinei_Otranto2012_Lesson-1
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Dear radioactive ladies and gentlemen,
[…] I have hit upon a desperate remedy to save
the "exchange theorem" of statistics and the
energy theorem. [… ] there could exist in the
nuclei electrically neutral particles that I wish to
call neutrons, which have spin 1/2 and obey the
exclusion principle, and additionally differ from
light quanta in that they do not travel with the
velocity of light. The mass of the neutron must
be of the same order of magnitude as the electron
mass and, in any case, not larger than 0.01
proton mass. The continuous ß-spectrum would
then become understandable [...] But I don't feel
secure enough to publish anything about this
idea […] However, only those who wager can win,
and the seriousness of the situation of the
continuous ß-spectrum can be made clear by the
saying of my honored predecessor in office, Mr.
Debye, [...] "One does best not to think about that
at all, like the new taxes."
Ioan Dafinei
INFN Sezione di Roma, ITALY
introduction
Cosmic Gall
NEUTRINOS, they are very small.
They have no charge and have no mass
And do not interact at all.
The earth is just a silly ball
To them, through which they simply pass,
Like dustmaids down a drafty hall
Or photons through a sheet of glass.
They snub the most exquisite gas,
Ignore the most substantial wall,
Cold shoulder steel and sounding brass,
Insult the stallion in his stall,
And scorning barriers of class,
Infiltrate you and me! Like tall
and painless guillotines, they fall
Down through our heads into the grass.
At night, they enter at Nepal
and pierce the lover and his lass
From underneath the bed-you call
It wonderful; I call it crass.
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
neutrinos have no mass
(only charged leptons obtain an effective mass
through interaction with the Higgs field)
no mixing of the different
generations of charged leptons
(as there is for quarks)
John Updike
Telephone Poles and Other Poems, Knopf 1960
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrino mass challenge
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
neutrino oscillation
(predicted by Bruno Pontecorvo)
a neutrino created with a specific
lepton flavor can later be measured
to have a different flavor
the probability of measuring a
particular flavor for a neutrino varies
periodically as it propagates
experimental proofs
solar neutrino oscillation
deficit in the flux of solar neutrinos with respect to the prediction of the Standard Solar Model
•first detected by Homestake Experiment (run from 1970 until 1994):
•clear evidence of neutrino flavor change provided by Sudbury Neutrino Observatory in 2001
atmospheric neutrino oscillation
observed deficit in the ratio of the flux of muon to electron flavor atmospheric neutrinos
(IMB, MACRO, Kamiokande).
reactor neutrino oscillation
oscillation of electron anti-neutrinos produced at nuclear reactors
(KamLAND Double Chooz, RENO, Daya Bay)
beam neutrino oscillation
the same neutrino oscillations which take place in atmospheric neutrino oscillation, using
neutrinos with a few GeV of energy and several hundred km baselines
ex: the INFN and CERN observed (May 2010) a tau particle in a muon neutrino beam in the
OPERA detector (LNGS, Italy), 730 km away from the neutrino source (CERN, Geneva)
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrino mass challenge
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
neutrino oscillation implies
that the neutrino has a
non-zero mass which is not
provided by the original
Standard Model
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrino mass challenge
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
the small stump overturns
the large carriage…
neutrino oscillation implies
that the neutrino has a
non-zero mass which is not
provided by the original
Standard Model
?
there is physics beyond SM!
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrino mass challenge
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
the experiments dedicated to neutrino oscillation are the kind
of experiments that only PUT THE PROBLEM and possibly
give some hints but cannot GIVE THE SOLUTION
what is observed:
neutrinos are massive

oscillations do occur

get approximate values
for two of the DMij2

measure the 3 angles which parametrize the mixing matrix
(DMij2  Mi2 – Mj2)
Dafinei_Otranto2012_Lesson-1
atmospheric: |DM232| ~ (50 meV)2
solar:
|DM122 | ~ (9 meV)2
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrino mass challenge
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
the experiments dedicated to neutrino oscillation are the kind
of experiments that only PUT THE PROBLEM and possibly
give some hints but cannot GIVE THE SOLUTION
what remains unsolved:

absolute neutrino
mass scale

neutrino mass hierarchy

nature of neutrinos
Dafinei_Otranto2012_Lesson-1
degeneracy ?
(M1~M2~M3)
direct
inverted
v 
v 
DIRAC
MAJORANA
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrino challenges
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
critical questions for
neutrino physics
•what are the scale of neutrino masses?
•is there any degeneracy?
•which is the hierarchy of the neutrino mass ordering
•what is the neutrino mass/mixing matrix?
•why is it so different from quarks?
•do neutrinos violate the CP symmetry?
•contribution to the matter-antimatter asymmetry?
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
the double beta decay
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Abstract
From the Fermi theory of β-disintegration the probability of simultaneous
emission of two electrons (and two neutrinos) has been calculated. The
result is that this process occurs sufficiently rarely to allow a half-life of over
1017 years for a nucleus, even if its isobar of atomic number different by 2
were more stable by 20 times the electron mass.
M. Goepert-Mayer
Energy
Double beta-Disintegration, Phys.Rev. 48:512-16 (1935)
Dafinei_Otranto2012_Lesson-1
Forbidden
Characteristics:
Extremely rare decay, possible
only in few isotopes in which
single β decay is forbidden
Ioan Dafinei
INFN Sezione di Roma, ITALY
the double beta decay
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
possible decay modes
1
( A, Z )  ( A, Z  2)  2e   2 e
measured: t ~1018 – 1021 y
2n  2 p  2e   2 e
L: 0 = 0 +2
-2
allowed by the Standard Model
( A, Z )  ( A, Z  2)  2e 
2
L:
3
0 ≠ 0 +2 +0
(except a discussed claim)
t > 1025 y
2n  2 p  2e 
0 ≠ 0 +2
not allowed by the SM
( A, Z )  ( A, Z  2)  2e   
2n  2 p  2e   
L:
not observed till now
G. Racah
not observed till now
t > 1022 y
not allowed by the SM
E. Majorana
"majoron“ (neutral boson)
(postulated by Majorana)
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrinoless DBD
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
0νDBD
( A, Z )  ( A, Z  2)  2e 
0DBD
experimental limit: sensitivity
 10 y
•very rare process T1 / 2
•requires massive Majorana neutrinos
•forbidden by SM
( A, Z )  ( A, Z  2)  2e   2
Dafinei_Otranto2012_Lesson-1
25
S  N
mt
B  DE
ε: detection efficiency
N: number of ββ nuclides
t: measurement time
m: total mass
ΔE: energy resolution of the detector
B: background rate in the ROI
B needed:
<10-3 c/keV·kg·y
Ioan Dafinei
INFN Sezione di Roma, ITALY
0νDBD experiments
experimental methods
e-
Source  Detector
(calorimetric technique)




OTRANTO
21-27 Settembre 2012
 constraints on detector materials
 very large masses are possible
demonstrated: up to ~ 50 kg
proposed: up to ~ 1000 kg
e-

XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
scintillation
phonon-mediated detection
solid-state devices
gaseous/lquid detectors

with proper choice of the detector,
very high energy resolution
Ge-diodes
bolometers

in gaseous/liquid xenon detector,
indication of event topology
e- detector

source
e- detector
Source  Detector




Dafinei_Otranto2012_Lesson-1
scintillation
gaseous TPC
gaseous drift chamber
magnetic field and TOF

it is difficult to get large source mass

neat reconstruction of event topology

several candidates can be studied
with the same detector
Ioan Dafinei
INFN Sezione di Roma, ITALY
neutrinoless DBD
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
betting on 0νDBD
If evidenced:
expected:
0
1/ 2
-Majorana neutrino
-Neutrino mass measurement
-Lepton number violation
T
 10 y
24
Experiments measure
the process half-time (
Phase space
factor (∝Q5)
Dafinei_Otranto2012_Lesson-1
Nuclear
Matrix
Element
)
Effective
neutrino mass
Ioan Dafinei
INFN Sezione di Roma, ITALY
0νDBD experiments
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
peculiarities of 0νDBD
(choice of the nuclide)
Decay
208Tl
i.a.
[%]
Q [keV]
48Ca
→ 48Ti
0.187
4271
76Ge
→ 76Se
7.8
2040
82Se
→ 82Kr
9
2995
94Zr
→ 94Mo
17.4
1145
96Zr
→
96Mo
2.8
3350
→ 100Ru
9.6
3034
110Pd
→ 110Cd
11.7
2013
116Cd
→ 116Sn
7.5
2802
124Sn
→ 124Te
5.8
2288
130Te
→ 130Xe
34.2
2528
136Xe
→ 136Ba
8.9
2479
150Nd
→ 150Sm
5.6
3367
100Mo
Dafinei_Otranto2012_Lesson-1
76Ge
130Te
116Cd
100Mo
82Se
Ioan Dafinei
INFN Sezione di Roma, ITALY
0νDBD experiments
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
peculiarities of 0νDBD
(experimental site)
Laboratori Nazionali del Gran Sasso (LNGS)
•
•
•
•
•
Dafinei_Otranto2012_Lesson-1
largest underground laboratory in the world for experiments
in particle physics, particle astrophysics and nuclear
astrophysics
experiments that require a low background environment
current main research topics: neutrino physics, dark matter
search, nuclear reactions of astrophysical interest
used as a worldwide facility by scientists from 22 different
countries
over 20 experiments on the way
Ioan Dafinei
INFN Sezione di Roma, ITALY
the bolometer technique and 0νDBD
principles
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
E. Fiorini
P. Debye
For sufficiently low temperatures, the
specific heat is proportional to the third
power of the absolute temperature.
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
the bolometer technique and 0νDBD
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
phonon mediated particle detectors
phonon sensors:
(functioning principle)
•
Semiconductor Thermistors
heat sink
(T  10-100 mK)
below D
C ~ (T/D)3
(dielectric, diamagnetic
materials are preferred)
incident
particle (E)
thermal coupling
(very weak)
G  4 pW/mK
thermometer
energy
absorber
Rload
•
Transition Edge Sensors
•
Superconductive Tunnel Junctions
•
Kinetic Inductance Thermometers
•
Capacitive Thermometers
Typical thermistors used in LTD:
 Neutron Transmutation Doped (NTD) Ge thermistors
Ge crystal exposed to neutron bombardment
neutron capture and subsequent β and EC decay
neutron dose controls final doping (typically 6·1016 cm-3)
 Si-implanted thermistors
standard microelectronic technology
ionic implantation of P or As (n doping) or B (p doping)
typical doping levels 6·1018 cm-3
1




below 10K :  (T )   0  exp (T / T0 ) 2 
T0 and ρ0 are controlled through doping
signal DR ~ DT = E/C
relaxation time t = C/G
R(T)
Rload
dR/dε  20 k/keV
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
the bolometer technique
dilution refrigerators
(functioning principles)
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
3He-4He
phase diagram
3He
concentration in the mixture
•provides continuous cooling
to temperatures up to 2 mK
without moving parts in the
low-temperature region
•is based on the 3He-4He
mixture spontaneous
separation below 870 mK
•the transfer of 3He from
concentrated phase to dilute
phase is endothermic
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
dilution refrigerator
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Mixing Chamber
Stainless steel wire
Light Detectors
First damping mass
(Roman Lead)
S.Pirro (2005)
Dafinei_Otranto2012_Lesson-1
CUORE Radiaoctivity
test run
(II Damping stage)
Ioan Dafinei
INFN Sezione di Roma, ITALY
the bolometer technique
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
dilution refrigerator example
(courtesy: Laboratorio di Criogenia di Como)
pulse tube
precooling
cryostat
gas control
system
compressor
(precooling)
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
the bolometer technique
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
the thermistor
neutron transmutation doping (NTD):
creation of non-radioactive impurity
isotopes from the host atoms of a
material by thermal neutron irradiation
and subsequent radioactive decay
the method is used because:
•allows for an excellent control of the
spatial uniformity of doping
•makes a precision target doping
(≈1% or better)
•gives no microresistivity structure
E.E. Haller, K.M. Itoh and J.W. Beeman, LBNL-38912 (1996)
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
the bolometer technique
bolometric detection example
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
(courtesy: CUORICINO experiment)
Dafinei_Otranto2012_Lesson-1
Ioan Dafinei
INFN Sezione di Roma, ITALY
next lesson
XXIV SEMINARIO NAZIONALE
Di FISICA NUCLEARE E
SUBNUCLEARE
OTRANTO
21-27 Settembre 2012
Argomento: Studio del decadimento doppio beta ai LNGS
Lezione 2: Esperimenti CUORE e LUCIFER
•
•
•
•
•
•
Dafinei_Otranto2012_Lesson-1
double beta decay study at LNGS
cryogenic bolometers; insights
CUORE and CUORE-0 experiments
scintillating bolometers
LUCIFER experiment
large scale crystal production issue
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.
L.M. Brown, The idea of the neutrino , Phys. Today 31(9), 23 (1978)
2.
S.R. Elliot and P. Vogel, DOUBLE BETA DECAY, Annu. Rev. Nucl. Part. Sci. 2002. 52:115–51
3.
W. Pauli (1930), Pauli Letter Collection, https://cdsweb.cern.ch/record/83282?ln=it
4.
M. Goeppert-Mayer, "Double Beta-Disintegration", Phys.Rev. 48 (1935) 512-516
5.
V. Gribov and B. Pontecorvo, NEUTRINO ASTRONOMY AND LEPTON CHARGE, Physics Letters B 28:493 (1969)
6.
E. Fiorini and T.O. Niinikoski, LOW-TEMPERATURE CALORIMETRY FOR RARE DECAYS, CERN-EP/83-180, 17 Nov. 1983
7.
P. Debye, "Zur Theorie der spezifischen Waerme". Annalen der Physik (Leipzig) 39 (4): 789-839 (1912)
8.
E.E. Haller, K.M. Itoh and J.W. Beeman, NEUTRON TRANSMUTATION DOPED (NTD) GERMANIUM THERMISTORS FOR
SUB-MM BOLOMETER APPLICATIONS LBNL-38912 30th ESLAB Symposium, "Submillimetre and Far-Infrareded Space
Instrumentation" Noordwijk, The Netherlands, Sept. 24-26,1996
Dafinei_Otranto2012_Lesson-1
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-1
Ioan Dafinei
INFN Sezione di Roma, ITALY