6 research outputs found
The Electronics and Data Acquisition System of the DarkSide Dark Matter Search
It is generally inferred from astronomical measurements that Dark Matter (DM)
comprises approximately 27\% of the energy-density of the universe. If DM is a
subatomic particle, a possible candidate is a Weakly Interacting Massive
Particle (WIMP), and the DarkSide-50 (DS) experiment is a direct search for
evidence of WIMP-nuclear collisions. DS is located underground at the
Laboratori Nazionali del Gran Sasso (LNGS) in Italy, and consists of three
active, embedded components; an outer water veto (CTF), a liquid scintillator
veto (LSV), and a liquid argon (LAr) time projection chamber (TPC). This paper
describes the data acquisition and electronic systems of the DS detectors,
designed to detect the residual ionization from such collisions
DarkSide-50, a background free experiment for dark matter searches
The existence of dark matter is inferred from gravitational effects, but its nature remains a deep mystery. One possibility, motivated by considerations in elementary particle physics, is that dark matter consists of elementary particles, such as the hypothesized Weakly Interacting Massive Particles (WIMPs), with mass ~ 100 GeV and cross-section ~ 10â47 cm2, that can be gravitationally trapped inside our galaxy and revealed by their scattering on nuclei. It should be possible to detect WIMPs directly, as the orbital motion of the WIMPs composing the dark matter halo pervading the galaxy should result in WIMP-nucleus collisions of sufficient energy to be observable in the laboratory. The DarkSide-50 experiment is a direct WIMP search using a Liquid Argon Time Projection Chamber (LAr-TPC) with an active mass of 50 kg with a high sensitivity and an ultra-low background detector
First Results from the DarkSide-50 Dark Matter Experiment at Laboratori Nazionali del Gran Sasso
We report the first results of DarkSide-50, a direct search for dark matter operating in the un-
derground Laboratori Nazionali del Gran Sasso (LNGS) and searching for the rare nuclear recoils
possibly induced by weakly interacting massive particles (WIMPs). The dark matter detector is a
Liquid Argon Time Projection Chamber with a
(
46.4
0.7
)
kg active mass, operated inside a 30 t or-
ganic liquid scintillator neutron veto, which is in turn installed at the center of a 1 kt water Cherenkov
veto for the residual flux of cosmic rays. We report here the null results of a dark matter search for
a
(
1422
67
)
kg d exposure with an atmospheric argon fill. This is the most sensitive dark matter
search performed with an argon target, corresponding to a 90% CL upper limit on the WIMP-nucleon
spin-independent cross section of 6.1
1
The Electronics and Data Acquisition System of the DarkSide Dark Matter Search
It is generally inferred from astronomical measurements th
at Dark
Matter (DM) comprises approximately 27% of the energy-dens
ity of the universe.
If DM is a subatomic particle, a possible candidate is a Weakl
y Interacting Mas-
sive Particle (WIMP), and the DarkSide-50 (DS) experiment i
s a direct search for
evidence of WIMP-nuclear collisions. DS is located undergr
ound at the Laboratori
Nazionali del Gran Sasso (LNGS) in Italy, and consists of thr
ee active, embedded
components; an outer water veto (CTF), a liquid scintillato
r veto (LSV), and
a liquid argon (LAr) time projection chamber (TPC). This pap
er describes the
data acquisition and electronic systems of the DS detectors
, designed to detect
the residual ionization from
Fermi establishes classical novae as a distinct class of gamma-ray sources
A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in Îł rays and stood in contrast to the first Îł-ray-detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft-spectrum transient Îł-ray sources detected over 2- to 3-week durations. The Îł-ray detections point to unexpected high-energy particle acceleration processes linked to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic Îł-ray sources
Appropriateness of antiplatelet therapy for primary and secondary cardio- and cerebrovascular prevention in acutely hospitalized older people
Aims: Antiplatelet therapy is recommended for the secondary prevention of cardio- and cerebrovascular disease, but for primary prevention it is advised only in patients at very high risk. With this background, this study aims to assess the appropriateness of antiplatelet therapy in acutely hospitalized older people according to their risk profile. Methods: Data were obtained from the REPOSI register held in Italian and Spanish internal medicine and geriatric wards in 2012 and 2014. Hospitalized patients aged 6565 assessable at discharge were selected. Appropriateness of the antiplatelet therapy was evaluated according to their primary or secondary cardiovascular prevention profiles. Results: Of 2535 enrolled patients, 2199 were assessable at discharge. Overall 959 (43.6%, 95% CI 41.5\u201345.7) were prescribed an antiplatelet drug, aspirin being the most frequently chosen. Among patients prescribed for primary prevention, just over half were inappropriately prescribed (52.1%), being mainly overprescribed (155/209 patients, 74.2%). On the other hand, there was also a high rate of inappropriate underprescription in the context of secondary prevention (222/726 patients, 30.6%, 95% CI 27.3\u201334.0%). Conclusions: This study carried out in acutely hospitalized older people shows a high degree of inappropriate prescription among patients prescribed with antiplatelets for primary prevention, mainly due to overprescription. Further, a large proportion of patients who had had overt cardio- or cerebrovascular disease were underprescribed, in spite of the established benefits of antiplatelet drugs in the context of secondary prevention