10 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 ~ 10−47 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
Relations between measured and calculated spin observables in inelastic scattering of polarized protons for excitation of the 1+, T = 0 state in 12C
Linear and nonlinear techniques for multibeam joint processing in satellite communications
Existing satellite communication standards such as DVB-S2 operate under highly-efficient adaptive coding and modulation schemes thus making significant progress in improving the spectral efficiencies of digital satellite broadcast systems. However, the constantly increasing demand for broadband and interactive satellite links emanates the need to apply novel interference mitigation techniques, striving towards Terabit throughput. In this direction, the objective of the present contribution is to investigate joint multiuser processing techniques for multibeam satellite systems. In the forward link, the performance of linear precoding is investigated with optimal non-linear precoding (i.e. Dirty Paper Coding) acting as the upper performance limit. To this end, the resulting power and precoder design problems are approached through optimization methods. Similarly, in the return link the concept of linear filtering (i.e. Linear Minimum Mean Square Error) is studied with the optimal successive interference cancellation acting as the performance limit. The derived capacity curves for both scenarios are compared to conventional satellite systems where beams are processed independently and interbeam interference is mitigated through a four color frequency reuse scheme, in order to quantify the potential gain of the proposed techniques
Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer's disease.
We sought to identify new susceptibility loci for Alzheimer's disease through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimer's Disease Genetic Consortium (ADGC) in a companion paper. We undertook a combined analysis of four genome-wide association datasets (stage 1) and identified ten newly associated variants with P 64 1
7 10(-5). We tested these variants for association in an independent sample (stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (stage 3). Meta-analyses of all data provided compelling evidence that ABCA7 (rs3764650, meta P = 4.5
7 10(-17); including ADGC data, meta P = 5.0
7 10(-21)) and the MS4A gene cluster (rs610932, meta P = 1.8
7 10(-14); including ADGC data, meta P = 1.2
7 10(-16)) are new Alzheimer's disease susceptibility loci. We also found independent evidence for association for three loci reported by the ADGC, which, when combined, showed genome-wide significance: CD2AP (GERAD+, P = 8.0
7 10(-4); including ADGC data, meta P = 8.6
7 10(-9)), CD33 (GERAD+, P = 2.2
7 10(-4); including ADGC data, meta P = 1.6
7 10(-9)) and EPHA1 (GERAD+, P = 3.4
7 10(-4); including ADGC data, meta P = 6.0
7 10(-10))