Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARE
Neutrinoless Double Beta Decay Experiments
I. DafineiUniversità "La Sapienza" di Roma and Sezione INFN - Roma
made in the frame of LUCIFER experimentFP7/2007-2013ERC grant agreement n. 247115.
Lucifer
XXIV SEMINARIO NAZIONALE di FISICA NUCLEARE E SUBNUCLEAREOTRANTO, Serra degli Alimini, 21-27 Settembre 2012 Argomento: Studio del decadimento doppio beta ai LNGSLezione 1: Il decadimento doppio beta senza neutrini
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARE
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 DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREintroduction
… so what?
neutrino has a mass!
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)
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREintroduction
Seventh Solvay Conference on Physics, Brussels 1933
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."
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREintroduction
Cosmic GallNEUTRINOS, 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.
John UpdikeTelephone Poles and Other Poems, Knopf 1960
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)
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrino mass challengeneutrino oscillation
(predicted by Bruno Pontecorvo)
solar neutrino oscillationdeficit 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
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
atmospheric neutrino oscillationobserved deficit in the ratio of the flux of muon to electron flavor atmospheric neutrinos (IMB, MACRO, Kamiokande).
reactor neutrino oscillationoscillation of electron anti-neutrinos produced at nuclear reactors(KamLAND Double Chooz, RENO, Daya Bay)
beam neutrino oscillationthe same neutrino oscillations which take place in atmospheric neutrino oscillation, using neutrinos with a few GeV of energy and several hundred km baselinesex: 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)
experimental proofs
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrino mass challenge
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 DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrino mass challenge
neutrino oscillation implies that the neutrino has a non-zero mass which is not provided by the original Standard Model
the small stump overturns the large carriage…
?
there is physics beyond SM!
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrino mass challenge
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:
measure the 3 angles which parametrize the mixing matrix
get approximate values for two of the Mij
2solar: |M12
2 | ~ (9 meV)2
atmospheric: |M232| ~ (50 meV)2
(Mij2 Mi
2 – Mj2)
oscillations do occur neutrinos are massive
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrino mass challenge
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 degeneracy ? (M1~M2~M3)
neutrino mass hierarchy
direct inverted
nature of neutrinosDIRAC
MAJORANA
vv
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrino challengescritical 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 DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe double beta decay
Forbidden
Ener
gy
Extremely rare decay, possible only in few isotopes in which single β decay is forbidden
Characteristics:
AbstractFrom 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
Double beta-Disintegration, Phys.Rev. 48:512-16 (1935)
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe double beta decaypossible decay modes
measured: ~1018 – 1021 yeeZAZA 22)2,(),(
eepn 2222
L: 0 = 0 +2 -2 allowed by the Standard Model
1
not observed till now(except a discussed claim) > 1025 y
eZAZA 2)2,(),( epn 222
L: 0 ≠ 0 +2 not allowed by the SM
2
not observed till now> 1022 y eZAZA 2)2,(),(
epn 222L: 0 ≠ 0 +2 +0 not allowed by the SM
3
"majoron“ (neutral boson)(postulated by Majorana)
G. Racah
E. Majorana
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrinoless DBD0νDBD
•very rare process•requires massive Majorana neutrinos •forbidden by SM
eZAZA 2)2,(),(
yT DBD 2502/1 10
22)2,(),( eZAZA
EBtm
NS
ε: detection efficiencyN: number of ββ nuclidest: measurement timem: total massΔE: energy resolution of the detectorB: background rate in the ROI
experimental limit: sensitivity
B needed:<10-3 c/keV·kg·y
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARE0νDBD experiments
e-
e-
Source Detector(calorimetric technique)
scintillation phonon-mediated detection solid-state devices gaseous/lquid detectors
very large masses are possible demonstrated: up to ~ 50 kg proposed: up to ~ 1000 kg
with proper choice of the detector, very high energy resolution
Ge-diodesbolometers
in gaseous/liquid xenon detector, indication of event topology
constraints on detector materials
neat reconstruction of event topology
it is difficult to get large source mass
several candidates can be studied with the same detector
e-
e-
source
detector
detector
Source Detector
scintillation gaseous TPC gaseous drift chamber magnetic field and TOF
experimental methods
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREneutrinoless DBD
16
Effective neutrino
mass
Nuclear Matrix
ElementPhase space factor (∝Q5)
Experiments measure the process half-time ( )
-Majorana neutrino-Neutrino mass measurement-Lepton number violation
If evidenced:
yT 2402/1 10
expected:
betting on 0νDBD
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARE0νDBD experimentspeculiarities of 0νDBD(choice of the nuclide)
Decay i.a. [%]
Q [keV]
48Ca → 48Ti 0.187 4271
76Ge → 76Se 7.8 204082Se → 82Kr 9 299594Zr → 94Mo 17.4 114596Zr → 96Mo 2.8 3350100Mo → 100Ru 9.6 3034110Pd → 110Cd 11.7 2013116Cd → 116Sn 7.5 2802124Sn → 124Te 5.8 2288130Te → 130Xe 34.2 2528136Xe → 136Ba 8.9 2479150Nd → 150Sm 5.6 3367
130Te76Ge
100Mo116Cd
82Se
208Tl
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARE0νDBD experimentspeculiarities of 0νDBD(experimental site)
• 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
Laboratori Nazionali del Gran Sasso (LNGS)
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe bolometer technique and 0νDBDprinciples
For sufficiently low temperatures, the specific heat is proportional to the third power of the absolute temperature.
E. Fiorini
P. Debye
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe bolometer technique and 0νDBDphonon mediated particle detectors (functioning
principle)
R ~ T = E/Csignal
dR/dε 20 k/keV
R(T)
Rload
Rload
relaxation time = C/G
phonon sensors:• Semiconductor Thermistors• 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 bombardmentneutron capture and subsequent β and EC decayneutron dose controls final doping (typically 6·1016 cm-3)
Si-implanted thermistorsstandard microelectronic technologyionic implantation of P or As (n doping) or B (p doping)typical doping levels 6·1018 cm-3
T0 and ρ0 are controlled through doping
2
1
00 )/(exp)( TTT below 10K :
thermal coupling(very weak)G 4 pW/mK
heat sink(T 10-100 mK)
energy absorber
below D
C ~ (T/D)3
(dielectric, diamagneticmaterials are preferred)
incident particle (E)
thermometer
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe bolometer techniquedilution refrigerators(functioning principles)
3He-4Hephase 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 DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARE
Mixing Chamber
Stainless steel wire
First damping mass(Roman Lead)
CUORE Radiaoctivitytest run
(II Damping stage)
Light Detectors
S.Pirro (2005)
dilution refrigerator
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe bolometer techniquedilution refrigerator example(courtesy: Laboratorio di Criogenia di Como)
gas control system
cryostat
compressor(precooling
)
pulse tubeprecooling
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe bolometer techniquethe thermistor
E.E. Haller, K.M. Itoh and J.W. Beeman, LBNL-38912 (1996)
neutron transmutation doping (NTD):creation of non-radioactive impurity isotopes from the host atoms of a material by thermal neutron irradiation and subsequent radioactive decaythe 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
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREthe bolometer techniquebolometric detection example(courtesy: CUORICINO experiment)
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREnext lessonArgomento: Studio del decadimento doppio beta ai LNGSLezione 2: Esperimenti CUORE e LUCIFER
• double beta decay study at LNGS• cryogenic bolometers; insights• CUORE and CUORE-0 experiments• scintillating bolometers• LUCIFER experiment• large scale crystal production issue
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEARErecommended bibliography
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. 52:115–513. W. Pauli (1930), Pauli Letter Collection, https://cdsweb.cern.ch/record/83282?ln=it4. M. Goeppert-Mayer, "Double Beta-Disintegration", Phys.Rev. 48 (1935) 512-5165. 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. 19837. 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
(.pdf files available upon request)
Dafinei_Otranto2012_Lesson-1
Ioan DafineiINFN Sezione di Roma, ITALY
OTRANTO21-27 Settembre 2012
XXIV SEMINARIO NAZIONALEDi FISICA NUCLEARE E
SUBNUCLEAREacknowledgements
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 / ERCgrant agreement n. 247115.