587 research outputs found
Statistical sensitivity of 163-Ho electron capture neutrino mass experiments
Large calorimetric neutrino mass experiments using thermal detectors are
possibly going to play a crucial role in the challenge for assessing the
neutrino mass. This paper describe a tool based on Monte Carlo methods which
has been developed to estimate the statistical sensitivity of calorimetric
neutrino mass experiments using the 163-Ho electron capture decay. The tool is
applied to investigate the effect of various experimental parameters and the
results useful for designing an experiment with sub-eV sensitivity are given.Comment: Accepted for publication in EPJ-
Expectations for a new calorimetric neutrino mass experiment
A large calorimetric neutrino mass experiment using thermal detectors is
expected to play a crucial role in the challenge for directly assessing the
neutrino mass. We discuss and compare here two approaches to the estimation of
the experimental sensitivity of such an experiment. The first method uses an
analytic formulation and allows to readily obtain a sensible estimate over a
wide range of experimental configurations. The second method is based on a
frequentist Montecarlo technique and is more precise and reliable. The
Montecarlo approach is then exploited to study the main sources of systematic
uncertainties peculiar to calorimetric experiments. Finally, the tools are
applied to investigate the optimal experimental configuration for a
calorimetric experiment with Rhenium based thermal detectors.Comment: 25 pagers, 16 figure
The MARE Project
The international project "Microcalorimeter Arrays for a Rhenium Experiment" (MARE) aims at a direct and calorimetric measurement of the electron antineutrino mass with sub-electronvolt sensitivity. MARE is divided in two phases. The first phase consists of two independent experiments using the presently available detector technology to reach a sensitivity of the order of 1 eV and to improve the understanding of the systematic uncertainties peculiar of this technique. In parallel to these experiments, a wide R&D program will single out the appropriate detector configuration, the read-out scheme and the large array technology for the second phase of MARE. In the second phase, the selected techniques will be applied to the realization of large arrays with as many as 10000 detectors each. At least five arrays will be then deployed to collect the statistics required to probe the antineutrino mass with a sensitivity of at least 0.2 eV, comparable to the one expected for the Katrin experiment (KATRIN Design Report, 2004)
Investigation of peak shapes in the MIBETA experiment calibrations
In calorimetric neutrino mass experiments, where the shape of a beta decay
spectrum has to be precisely measured, the understanding of the detector
response function is a fundamental issue. In the MIBETA neutrino mass
experiment, the X-ray lines measured with external sources did not have
Gaussian shapes, but exhibited a pronounced shoulder towards lower energies. If
this shoulder were a general feature of the detector response function, it
would distort the beta decay spectrum and thus mimic a non-zero neutrino mass.
An investigation was performed to understand the origin of the shoulder and its
potential influence on the beta spectrum. First, the peaks were fitted with an
analytic function in order to determine quantitatively the amount of events
contributing to the shoulder, also depending on the energy of the calibration
X-rays. In a second step, Montecarlo simulations were performed to reproduce
the experimental spectrum and to understand the origin of its shape. We
conclude that at least part of the observed shoulder can be attributed to a
surface effect
Critical Temperature tuning of Ti/TiN multilayer films suitable for low temperature detectors
We present our current progress on the design and test of Ti/TiN Multilayer
for use in Kinetic Inductance Detectors (KIDs). Sensors based on
sub-stoichiometric TiN film are commonly used in several applications. However,
it is difficult to control the targeted critical temperature , to maintain
precise control of the nitrogen incorporation process and to obtain a
production uniformity. To avoid these problems we investigated multilayer
Ti/TiN films that show a high uniformity coupled with high quality factor,
kinetic inductance and inertness of TiN. These features are ideal to realize
superconductive microresonator detectors for astronomical instruments
application but also for the field of neutrino physics. Using pure Ti and
stoichiometric TiN, we developed and tested different multilayer configuration,
in term of number of Ti/TiN layers and in term of different interlayer
thicknesses. The target was to reach a critical temperature around
K in order to have a low energy gap and slower recombination time
(i.e. low generation-recombination noise). The results prove that the
superconductive transition can be tuned in the K temperature
range properly choosing the Ti thickness in the nm range, and the
TiN thickness in the nm rang
Development of microwave superconducting microresonators for neutrino mass measurement in the HOLMES framework
The European Research Council has recently funded HOLMES, a project with the
aim of performing a calorimetric measurement of the electron neutrino mass
measuring the energy released in the electron capture decay of 163Ho. The
baseline for HOLMES are microcalorimeters coupled to Transition Edge Sensors
(TESs) read out with rf-SQUIDs, for microwave multiplexing purposes. A
promising alternative solution is based on superconducting microwave
resonators, that have undergone rapid development in the last decade. These
detectors, called Microwave Kinetic Inductance Detectors (MKIDs), are
inherently multiplexed in the frequency domain and suitable for even
larger-scale pixel arrays, with theoretical high energy resolution and fast
response. The aim of our activity is to develop arrays of microresonator
detectors for X-ray spectroscopy and suitable for the calorimetric measurement
of the energy spectra of 163Ho. Superconductive multilayer films composed by a
sequence of pure Titanium and stoichiometric TiN layers show many ideal
properties for MKIDs, such as low loss, large sheet resistance, large kinetic
inductance, and tunable critical temperature . We developed Ti/TiN
multilayer microresonators with within the range from 70 mK to 4.5 K and
with good uniformity. In this contribution we present the design solutions
adopted, the fabrication processes and the characterization results
The low-temperature energy calibration system for the CUORE bolometer array
The CUORE experiment will search for neutrinoless double beta decay (0nDBD)
of 130Te using an array of 988 TeO_2 bolometers operated at 10 mK in the
Laboratori Nazionali del Gran Sasso (Italy). The detector is housed in a large
cryogen-free cryostat cooled by pulse tubes and a high-power dilution
refrigerator. The TeO_2 bolometers measure the event energies, and a precise
and reliable energy calibration is critical for the successful identification
of candidate 0nDBD and background events. The detector calibration system under
development is based on the insertion of 12 gamma-sources that are able to move
under their own weight through a set of guide tubes that route them from
deployment boxes on the 300K flange down into position in the detector region
inside the cryostat. The CUORE experiment poses stringent requirements on the
maximum heat load on the cryostat, material radiopurity, contamination risk and
the ability to fully retract the sources during normal data taking. Together
with the integration into a unique cryostat, this requires careful design and
unconventional solutions. We present the design, challenges, and expected
performance of this low-temperature energy calibration system.Comment: To be published in the proceedings of the 13th International Workshop
on Low Temperature Detectors (LTD), Stanford, CA, July 20-24, 200
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