919 research outputs found
Status of the CUORE and CUORE-0 experiments at Gran Sasso
CUORE is a 741 kg array of TeO2 bolometers for the search of
neutrinoless double beta decay in 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/(keV·kg·y) will be reached, in five years of data taking CUORE will have a half life sensitivity of ⌠1026 y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of the CUORE and
CUORE-0 experiments will be presented
Focal Cerebral Infarction in Newborn: Description of Three Cases:
We observed 3 full-term newborns with focal ischemic injury of the middle cerebral artery (MCA), in which diagnosis of MCA stroke was suspected by US and confirmed by CT scan and MRI. A four-year follow-up was carried out to study the effect of neonatal stroke on neurodevelopmental outcome. All children had a history of pre-perinatal risk factors: neonatal cerebral infarction in term infants, in fact, has many possible causes, including bacterial meningitis, inherited or acquired coagulopathies, trauma and hypoxia-ischemia. The prognosis of neonatal MCA infarction depends on early diagnosis, on the CNS plasticity mechanism and, finally, on medical therapy and neuropsychological rehabilitation
New experimental limits on the alpha decays of lead isotopes
For the first time a PbWO4 crystal was grown using ancient Roman lead and it
was run as a cryogenic detector. Thanks to the simultaneous and independent
read-out of heat and scintillation light, the detector was able to discriminate
beta/gamma interactions with respect to alpha particles down to low energies.
New more stringent limits on the alpha decays of the lead isotopes are
presented. In particular a limit of T_{1/2} > 1.4*10^20 y at a 90% C.L. was
evaluated for the alpha decay of 204Pb to 200Hg
New application of superconductors: high sensitivity cryogenic light detectors
In this paper we describe the current status of the CALDER project, which is
developing ultra-sensitive light detectors based on superconductors for
cryogenic applications. When we apply an AC current to a superconductor, the
Cooper pairs oscillate and acquire kinetic inductance, that can be measured by
inserting the superconductor in a LC circuit with high merit factor.
Interactions in the superconductor can break the Cooper pairs, causing sizable
variations in the kinetic inductance and, thus, in the response of the LC
circuit. The continuous monitoring of the amplitude and frequency modulation
allows to reconstruct the incident energy with excellent sensitivity. This
concept is at the basis of Kinetic Inductance Detectors (KIDs), that are
characterized by natural aptitude to multiplexed read-out (several sensors can
be tuned to different resonant frequencies and coupled to the same line),
resolution of few eV, stable behavior over a wide temperature range, and ease
in fabrication. We present the results obtained by the CALDER collaboration
with 2x2 cm2 substrates sampled by 1 or 4 Aluminum KIDs. We show that the
performances of the first prototypes are already competitive with those of
other commonly used light detectors, and we discuss the strategies for a
further improvement
Characterization of the KID-Based Light Detectors of CALDER
The aim of the Cryogenic wide-Area Light Detectors with Excellent Resolution
(CALDER) project is the development of light detectors with active area of
cm and noise energy resolution smaller than 20 eV RMS,
implementing phonon-mediated kinetic inductance detectors. The detectors are
developed to improve the background suppression in large-mass bolometric
experiments such as CUORE, via the double read-out of the light and the heat
released by particles interacting in the bolometers. In this work, we present
the characterization of the first light detectors developed by CALDER. We
describe the analysis tools to evaluate the resonator parameters (resonant
frequency and quality factors) taking into account simultaneously all the
resonance distortions introduced by the read-out chain (as the feed-line
impedance and its mismatch) and by the power stored in the resonator itself. We
detail the method for the selection of the optimal point for the detector
operation (maximizing the signal-to-noise ratio). Finally, we present the
response of the detector to optical pulses in the energy range of 0-30 keV
TeO bolometers with Cherenkov signal tagging: towards next-generation neutrinoless double beta decay experiments
CUORE, an array of 988 TeO bolometers, is about to be one of the most
sensitive experiments searching for neutrinoless double-beta decay. Its
sensitivity could be further improved by removing the background from
radioactivity. A few years ago it has been pointed out that the signal from
s can be tagged by detecting the emitted Cherenkov light, which is not
produced by s. In this paper we confirm this possibility. For the first
time we measured the Cherenkov light emitted by a CUORE crystal, and found it
to be 100 eV at the -value of the decay. To completely reject the
background, we compute that one needs light detectors with baseline noise below
20 eV RMS, a value which is 3-4 times smaller than the average noise of the
bolometric light detectors we are using. We point out that an improved light
detector technology must be developed to obtain TeO bolometric experiments
able to probe the inverted hierarchy of neutrino masses.Comment: 5 pages, 4 figures. Added referee correction
Energy resolution and efficiency of phonon-mediated Kinetic Inductance Detectors for light detection
The development of sensitive cryogenic light detectors is of primary interest
for bolometric experiments searching for rare events like dark matter
interactions or neutrino-less double beta decay. Thanks to their good energy
resolution and the natural multiplexed read-out, Kinetic Inductance Detectors
(KIDs) are particularly suitable for this purpose. To efficiently couple
KIDs-based light detectors to the large crystals used by the most advanced
bolometric detectors, active surfaces of several cm are needed. For this
reason, we are developing phonon-mediated detectors. In this paper we present
the results obtained with a prototype consisting of four 40 nm thick aluminum
resonators patterned on a 22 cm silicon chip, and calibrated with
optical pulses and X-rays. The detector features a noise resolution
eV and an (182) efficiency.Comment: 5 pages, 5 figure
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