Transcript Numass2010_FGatti

MARE: Status and
Perspectives
Flavio Gatti
University and INFN of Genoa
on behalf of the MARE Collaboration
NUMASS2010
INT Seattle, Feb. 9, 2010
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MARE: a LTD experiment in R&D
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Rhenium (63%
EFW HM  
kT 2C
187Re)
Re Single Crystal (99,999%)

C~pJ @ 0.1K → mm3 size crystals →
arrays of detectors
15 crystals of this type
are needed for 0.2 eV
sensitivity experiment
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Calorimetric spectroscopy
Thermistor
Ir-Au TES on Si
Thermal contact
High purity
epoxy
Re Crystal
surfaces cleaned to optical level
annealed at 1300ºC in UHV
FALL TIME
(Depends on C, G, Bias Power)
Electrical & Heat link
Al -1% Si wires
15 μm diam., 1mm length
RISE TIME
(Depends on internal
Parameter Absorber-TES)
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MARE measurement challenges

Statistics → 1014

Unresolved pileup → 10-7
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Energy Resolution → 1 eV

Energy calibration → 10 -4
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Background → hope
negligible!

BEFS → know at very
precise level

Possible unknown
systematics → under
continuous investigation (we
are at the frontiers…)
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Sensitivity and uncertainties of
array based experiment
A.Nucciotti
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MARE-I: assessment of methods
and technology
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The full MARE experiment is still in the R&D phase and multiple options are being
evaluated.
Mainly: 2 options for b-isotopes, 2 option for the detector technology
ISOTOPE
187Re
TECHNOLOGY
163Ho
TES
MagCal
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Current Developments
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Re-TES array: Genoa-Miami
AgReO –Si array: Milan-Wisconsin-Goddard
MUX Readout: PTB-Genoa
Kinetic Inductance Sensors: Insubria-IRSTTrento
Magnetic Calorimeter: Heidelberg
GEANT simulation and data Analysis: Florida-Miami
MC modeling for experiment design: Milan
Ho-163: Genoa-Lisboa/ISOLDE CERN-Goddard
Production and study of low Q E.C. isotopes: GSI
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Re-TES detector prototypes (Genoa)
•Improve detector pulse rise-time to usec;
•Improve energy resolution from 10 eV (presently) to few eV;
•Large arrays (K-pixels) in order to achieve 104 -105 detectors in small volume;
•Provide an array design fully compatible with the requirements of a high precision
experiment (high reproducibility, stability, fully energy calibrated,…);
•Multiplexed read-out with large bandwidth (> 300 KHz) per channel;
Re crystal
Re-crystal on epoxy-post / Ir-TES / SiN-membrane
Al leads for TES
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Pilot experiment of 72 detector
array (Milan)
Single crystal of silver perrhenate
(AgReO4) as absorber
mass ~ 500 mg per pixel (Ab~
0.3 decay/sec)
regular shape (600x600x250
mm3)
low heat capacity due to Debye
law
6x6 array of Si thermistors
(NASA/GSFC)
pixel: 300x300x1.5 mm3
high energy resolution
developed for X-ray spectroscopy
300 mm
Si
support
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Metallic Magnetic Calorimeters
temperature rise upon absorption:
recovery time:
 Operation at low temperatures (T<100mK)
small heat capacity
large temperature change
paramagnetic sensor:
Au:Er
M
signal size:
small thermal noise
T
 Main differences to resistive calorimeters
no dissipation in the sensor
no galvanic contact to the sensor
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University of Heidelberg
Kirchhoff- Institute for Physics
 Planar sensors on meander shaped pickup coils
 Energy resolution
EFWHM = 2.8 eV @ 6 keV
55Mn
EFWHM= 2.65 eV @ 0 keV
baseline
 Expected energy resolution for next produced detectors <2 eV
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Micro-fabricated x-ray detectors
 Planar sensors on meander shaped pickup coils
 Energy resolution
 Rise time
rise time: 90 ns @ 30 mK
as expected from Korringa-constant for Er in Au
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MMC
for
Neutrino
Mass
experiments
MMCs for Neutrino Mass Experiments
 Optimization of MMCs with superconducting rhenium absorber
- minimization of the rise-time
- investigation of energy down-conversion in superconducting absorbers
- investigating the energy resolution achievable with superconducting absorber
A
B
Improvements in the rise-time:
A. manualy assembled detector ~1ms
B. sensor deposited directly on the Re
absorber ~20ms
Achievable rise-time ≤1ms
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MMC
for
Neutrino
Mass
experiments
MMCs for Neutrino Mass Experiments
 Optimization of MMCs with superconducting rhenium absorber
- minimization of the rise-time
- investigation of energy down-conversion in superconducting absorbers
- investigating the energy resolution achievable with superconducting absorber
 Calorimetric investigation of new candidates for the neutrino mass direct
measurements by electron capture decay
- 163Ho, 157Tb, 194Hg, 202Hg
- Development of micro-structured MMCs
for ion implantation at ISOLDE
- First detector with implanted 163Ho ready to run
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Genoa-PTB development on MUX readout
Enhanced Bandwidth requirement respect to X- ray det. readout
Ic1(f1,f2,f3)
Ic2(f1,f2,f3)
Ic3(f1,f2,f3)
Ib(f1)
TES12
TES11
Mxs
Mxs
RST1
Mxs
Mc
Mc
Mc
C1
Ib(f2)
TES13
C1
TES21
C1
TES23
TES22
Mxs
Mxs
Mxs
RST2
C2
C2
C2
Mf
Ib(f3)
TES32
TES31
Mxs
Mxs
Mxs
C3
C3
RST3
Lin
C3
FDM readout
scheme under
study at Genoa
Mf
Mf
Rf
TES33
PTB SQUID under test
at Genoa
Rf
Rf
Lin
Lin
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A second isotope for neutrino mass
calorimetric measurements: 163Ho
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N1
O1
M1
4
10
6
N2
M2
Signal / a.u.
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We have already (10 year ago) performed some test experiment with Ho-163
(F.Gatti, etal.1997)
163Ho 163Dy* + n
e
163Dy* decays via Coster-Kronig transition nS, nP
1/2
Breit Wigner M,N,O lines have an end-point at the Q value finite neutrino mass
causes a kink at the end-point similarly to beta spectra of 187-Re.
The major issue has been the preparation of the absorbers and the overall detector
performance that was unsatisfactory due to the not uniform absorber.
Signal / a.u.
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3
10
2
10
M1
M1
4
mn=2 eV
2
1
mn=0 eV
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Q=2580 eV
Q=2300 eV
M 2 , N i, O i
(i=1,2)
0
10
0
500
1000
1500
E / eV
2000
2500
0
2577,0
2577,5
2578,0
2578,5
2579,0
2579,5
2580,0
E / eV
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Previous test
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In the past we made a tentative experiment to verify the feasibility of a measurements
Ho-163 Cl solution from ISOLDE (E Laesgaard) after a tentative made by INRMoscow (purification failed)
Many effort for production of electroplated tin foils from organic solution at high
voltage
Final result was an admixture of fine salt grain onto tin matrix
 not satisfactory E resolution
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But
163Ho
is very attractive
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Advantages:
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tunable source activity independent form the absorber masses
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Minimization of the absorber mass to the minimum required by the full absorption
of the energy cascade  resolution less dependent from the activity
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Rise-time much less of 10 us for SiN suspended detector
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Higher Counting rate per detector 102 c/s
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Self calibrating experiment
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Easiest way to reach higher count rate with presently better performing detectors
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Implantation tests have been done at ISOLDE (CERN) as product of spallation of Ta
target by energetic proton and magnetic selection
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First sample contains high level of radioactive impurities
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Defined an alternative solution: neutron activation of enriched 162 Er , chemical
processing to achieve metallic state, implantation at ISOLDE or LISBOA facility
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163Ho
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sensitivity
With 2eV detectors (X-ray type) a great step forward in overall sensitivity and
detector integration for neutrino mass should be achieved
187-Re and 163-Ho should provide very low systematic measurement
Negligible pile-up
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Ho-163 in Goddard Array
163Ho
TES array from NASA/GSFC
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163Ho
studies
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Study of the B.-W. shape far from the maximum and intrinsic line-width, other
possible systematics
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Simulation under way for simulating sensitivity in realistic condition including the
pile-up and the uncertainties on Q value
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A high spectral resolution measurement is needed to fix the Q value and other
decay parameters.
signal
Where Q is
located?
Pile-up
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GEANT simulation of whole
experiment (Miami-Florida)
1.
Unidentified pileup
2.
Effect of the decay position in the absorber
3.
Efficiency and systematics of the analysis tools
4.
Background events originating from radioactive
decays in the surrounding cryostat material
(also activated by cosmics)
8x108 events
1 mg detector
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Summary
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MARE-I developments are going to the end
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An array of 72 channel is starting taking data taking for testing multiple detector experiment
Study for detector-abosber coupling for Re or Ho are under way and have define the strategy
Detectors with 1-2 eV energy resolution and 0.1 us time resolution are becoming
available
Electronics, Simulation, Data Analysis have defined the roadmap
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Technology almost ready and but need to be fully exploited and scaled to high
detector multiplicity.
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In the next 1-2years a decision on the isotope and detector technology should be
made and a prototype for MARE II detector built.
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MARE-II is a challenging experiment, but feasible.

Full development could start immediately after that (if funding is available both in the
US and Europe)
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We are more confident that MARE will provide fully complementary results to KATRIN
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Backup Slides
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187-Re decay in a crystal: case of Rhenium
Metal.

Initial and final states are in the crystal
The spectrum end-point energy is lower than the one
of isolated isotope.
 Eendpoint=(Q-mec2)-(ef+EFermi)-Blattice
where
 EFermi =11.2 eV,
 Work function f =5.1 eV
 Crystal binding energy Blattice = 16.9 eV
 Change of binding from Re->Os Blattice =2.7% Blattice

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187-Re decay in a crystal: case of
Rhenium Metal.
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75 Re [Xe] 4f14 5d5 6s2, Etot= -429402.3 eV
76 Os+ [Xe] 4f14 5d6 6s1, Etot= -443164.5 eV
76 Os
[Xe] 4f14 5d6 6s2, Etot=-443172.8 eV

Bcoul = -13.7 keV !
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the bare 187-Re cannot undergo continuum b-decay. Bound state decay
of 187Re75+ has been observed in storage ring having 32 y half life and
63KeV Q value
During the decay the beta particle pass through the atom. The electron
may not have the time to rearrange the electrons, the difference of atomic
binding energy Re-Os+ is very close to the binding energy difference of
the initial end final atomic state
Being the energy of the final state Os+ after the decay almost the one of
the ground state of Os+, high excited state of the final atom are very
unlikely
Further, due to the very similar atomic wave-function the probability of a
transition toward an excited state is very small being Os* eigenstate
orthogonal to the one of Re. A first evaluation of this probability is 7x10-5.
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187-Re decay in a crystal: case of
Rhenium Metal.
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Recoil energy at level of few meV respect to several eV per
dislocations; recoil contribute directly to the generation of
phonon of elastic branch.
Recoil free beta decay (not yet observed) but extending
Mossbauer and tacking into account the so small recoil effect,
this should be negligible.
Shake off probability at 1% level only for N and O shells, that
can emits photons of 50 eV (avg) or Auger electron. They are
fully absorbed in hundreds of Ang.
Inner Bremsstrahlung: same Q value but larger penetration
depth, however at um level
External Bremsstrahlung: can be fully contained as before
Collective excitation: based on long living quasi-particle states
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Low Temperature Magnetic Calorimeters for
Neutrino Mass Direct Measurement
L. Gastaldo, J.P. Porst , F. von Seggern , A. Kirsch ,
P. Ranitzsch , A. Fleischmann and C. Enss
University of Heidelberg
Kirchhoff- Institute for Physics
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