403 research outputs found
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
Y RNA: an overview of their role as potential biomarkers and molecular targets in human cancers
Y RNA are a class of small non-coding RNA that are largely conserved. Although their discovery was almost 40 years ago, their function is still under investigation. This is evident in cancer biology, where their role was first studied just a dozen years ago. Since then, only a few contributions were published, mostly scattered across different tumor types and, in some cases, also suffering from methodological limitations. Nonetheless, these sparse data may be used to make some estimations and suggest routes to better understand the role of Y RNA in cancer formation and characterization. Here we summarize the current knowledge about Y RNA in multiple types of cancer, also including a paragraph about tumors that might be included in this list in the future, if more evidence becomes available. The picture arising indicates that Y RNA might be useful in tumor characterization, also relying on non-invasive methods, such as the analysis of the content of extracellular vesicles (EV) that are retrieved from blood plasma and other bodily fluids. Due to the established role of Y RNA in DNA replication, it is possible to hypothesize their therapeutic targeting to inhibit cell proliferation in oncological patients
Non-coding RNAs and endometrial cancer
Non-coding RNAs (ncRNAs) are involved in the regulation of cell metabolism and neoplastic transformation. Recent studies have tried to clarify the significance of these information carriers in the genesis and progression of various cancers and their use as biomarkers for the disease; possible targets for the inhibition of growth and invasion by the neoplastic cells have been suggested. The significance of ncRNAs in lung cancer, bladder cancer, kidney cancer, and melanoma has been amply investigated with important results. Recently, the role of long non-coding RNAs (lncRNAs) has also been included in cancer studies. Studies on the relation between endometrial cancer (EC) and ncRNAs, such as small ncRNAs or micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), antisense RNAs (asRNAs), small nuclear RNAs (snRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), competing endogenous RNAs (ceRNAs), lncRNAs, and long intergenic ncRNAs (lincRNAs) have been published. The recent literature produced in the last three years was extracted from PubMed by two independent readers, which was then selected for the possible relation between ncRNAs, oncogenesis in general, and EC in particular
A New Limit on the Neutrinoless DBD of 130Te
We report the present results of CUORICINO a cryogenic experiment on
neutrinoless double beta decay (DBD) of 130Te consisting of an array of 62
crystals of TeO2 with a total active mass of 40.7 kg. The array is framed
inside of a dilution refrigerator, heavily shielded against environmental
radioactivity and high-energy neutrons, and operated at a temperature of ~8 mK
in the Gran Sasso Underground Laboratory. Temperature pulses induced by
particle interacting in the crystals are recorded and measured by means of
Neutron Transmutation Doped thermistors. The gain of each bolometer is
stabilized with voltage pulses developed by a high stability pulse generator
across heater resistors put in thermal contact with the absorber.
The calibration is performed by means of two thoriated wires routinely
inserted in the set-up. No evidence for a peak indicating neutrinoless DBD of
130Te is detected and a 90% C.L. lower limit of 1.8E24 years is set for the
lifetime of this process. Taking largely into account the uncertainties in the
theoretical values of nuclear matrix elements, this implies an upper boud on
the effective mass of the electron neutrino ranging from 0.2 to 1.1 eV. This
sensitivity is similar to those of the 76Ge experiments.Comment: 4 pages, 2 figure
The Microcalorimeter Arrays for a Rhenium Experiment (MARE): a next-generation calorimetric neutrino mass experiment
Neutrino oscillation experiments have proved that neutrinos are massive
particles, but can't determine their absolute mass scale. Therefore the
neutrino mass is still an open question in elementary particle physics. An
international collaboration is growing around the project of Microcalorimeter
Arrays for a Rhenium Experiment (MARE) for directly measuring the neutrino mass
with a sensitivity of about 0.2eV/c2. Many groups are joining their experiences
and technical expertise in a common effort towards this challenging experiment.
We discuss the different scenarios and the impact of MARE as a complement of
KATRIN.Comment: 3 pages, 1 figure Nucl. Instr. Meth. A, proceedings of LTD11
workshop, Tokyo 200
Majorana Neutrino Mixing
The most plausible see-saw explanation of the smallness of the neutrino
masses is based on the assumption that total lepton number is violated at a
large scale and neutrinos with definite masses are Majorana particles. In this
review we consider in details difference between Dirac and Majorana neutrino
mixing and possibilities of revealing Majorana nature of neutrinos with
definite masses
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