Scientific Open-access Literature Archive and Repository
Not a member yet
16397 research outputs found
Sort by
Study of the cosmic rays with the DAMPE experiment
No full textThe DArk Matter Particle Explorer (DAMPE) is a spaceborne
experiment, installed on board an instrumented satellite, launched on 17 December 2015 into a Sun-synchronous orbit at an altitude of about 500 km. The detector is smoothly taking data since then and has collected more than 5 · 109 cosmic rays events in 3 years. DAMPE is the result of an active cooperation between Italy, China and Switzerland in order to pursue the following scientific goals: indirect
research of dark matter particles, study of cosmic rays spectrum and high-energy gamma-ray astronomy. DAMPE is designed to operate for at least three years, and will probably be extended to a longer lifetime given the excellent current instrument status. In this paper the latest data analysis results will be presented
Reconstruction algorithms for identification of cosmic rays antinuclei with the GAPS experiment
No full textThe General Antiparticle Spectrometer (GAPS) is a balloon-borne detector designed to measure low-energy (<0.25 GeV/n) antideuteron cosmic ray component as a low-background signal from dark matter annihilation or decay in the Galactic halo. The detector consists of a tracker, made up by ten planes of lithium-drifted silicon detectors, surrounded by a plastic scintillator time-of-flight (ToF) system. GAPS uses a novel technique for particle identification based on the formation and decay of exotic atoms. Here we present preliminary results for
two reconstruction algorithms, one based on a classical approach and one on a deep learning approach, that have been tested on simulated events
Observation of CP violation in an amplitude analysis of B+ → π+π+π− decays
No full textThe violation of charge-parity (CP) symmetry in the Standard Model is driven by a single global phase, however manifestations of CP-violating quantities are non-trivial due to the essential role of the strong interaction in generating observable CP violation effects. Here we explore how the role of the strong phase in B+ → π+π+π− decays, described by the intermediate resonance structure and final-state rescattering effects, governs the manifestation of large CP violation
Performaces of the ATLAS New Small Wheel micromegas chambers at the CERN Gamma Ray Irradiation Facility
No full textOne of the main upgrades of the ATLAS Experiment during LongShutdown II is the replacement of the forward muon spectrometer inner station, the Small Wheel. The New Small Wheel, covering the pseudorapidity region 1.3 <η< 2.7, adopts micromegas micro pattern gas detectors for the muons precision tracking. Before the installation within the ATLAS Detector, micromegas chambers are tested under irradiation at the CERN Gamma Ray Irradiation Facility (GIF++)
CYGNO: Light Dark Matter search with an optically readout TPC
No full textCYGNO is a project realising a cubic meter demonstrator to study the performance of the optical approach for the readout of large-volume, GEMequipped TPC. This is part of the CYGNUS proto-collaboration which aims at constructing a network of underground observatories for directional Dark Matter search. The combined use of high-granularity sCMOS and fast sensors for reading out the light produced in GEM channels during the multiplication processes was
shown to allow on one hand to reconstruct 3D direction of the tracks, offering accurate energy measurements and sensitivity to the source directionality and, on the other hand, a high particle identification capability very useful to distinguish nuclear recoils
J/ψ decays into baryon-antibaryon pairs
No full textIn 2019 the BESIII Collaboration collected a sample of 10 billions of J/ψ events and, using about 1.3 × 109 of them, observed baryon polarization in baryon-antibaryon decays, publishing a paper in Nature Physics. Using new data from both PDG and BESIII experiment and a model based on an effective strong Lagrangian, we separate, for the first time, the strong and electromagnetic contributions to the total branching ratio of the J/ψ decays into a pair of spin-1/2 baryon-antibaryon, finding a relative phase of ϕ = (73 ± 8)◦
Matrix metalloproteases regulation in colorectal adenocarcinoma cells exposed to X-rays
No full textMatrix metalloproteases (MMPs) are degradation enzymes that allow cells to migrate through the extracellular matrix. MMPs generate new binding sites for tumour cell receptors that stimulate migration and invasion of normal
tissues, leading to metastasis. In our Radiation Biophysics and Radiobiology Laboratory we have started an extensive experimental characterization of the response to
X-rays (up to 10 Gy) of Caco-2 cells: this cell line is derived from human colorectal adenocarcinoma, usually adopted as an intestinal barrier model and recently characterized as radio-resistant. Colorectal cancer is among the three top cancer types for incidence and the second for mortality, usually treated with surgery, chemotherapy and radiotherapy. We performed gelatine zymography analysis, to evaluate MMP-2 and MMP-9 activity, which has been little investigated as a function of radiation dose and time after exposure. We here report results on the dose-dependent inhibition of these MMPs, also showing that measurements of MMPs activation can be
severely affected by the choice of the experimental protocol, and particularly by the temporal sequence of radiation treatment and cell seeding
Radon measurements in drinking water using electret according to Italian legislation and mapping of Campania region (Southern Italy)
No full textIn this study the radon-222 activity concentration in drinking water over a large area of the western Campania region was investigated. Water samples were collected over a period of three years between May 2017 and May 2019
in compliance with Italian legislation. The measurement of radon activity concentration using electret detector (E-PermR system) in short-short term configuration was performed. The purpose has been to identify the sampling points and report them on a map, studying the presence of any correlations between variations in the concentration of activity, seasonality and specific characteristics of the plant. The results obtained revealed that the concentrations of radon activity in the drinking water of the investigated sites are below the parameter value established by the law. Furthermore, activity concentration of radon in well water does not depend on
seasonality, unlike the tanks, for which there is a relationship with the temperature that must be studied separately on the basis of the single tank
Radiolytic effects on actinide(III) complexation with a hydrophilic PyTri ligand
No full textThe selective Am and Cm recovery from the highly active raffinate could be achieved by innovative-Selective ActiNide EXtraction (i-SANEX) process downstream major actinides removal. The TetraOctyl-DiGlycolAmide (TODGA)
extractant and a hydrophilic complexing agent, 2,6-bis[1-(propan-1-ol)-1,2,3-triazol4-yl)]pyridine (PTD) being the most promising one, could be synergically used to separate Am and Cm from chemically similar lanthanides. Besides promising selectivity and efficiency for Am and Cm extraction, such systems must prove radiolytic and hydrolytic stability, given the high radionuclide content of the feed. In this work, PTD selectivity for trivalent Am and Cm towards Eu, chosen as representative lanthanides, has been studied at relevant conditions by different spectroscopic techniques. In order to mimic the process conditions, solutions of PTD were γ-irradiated up to 200 kGy by a 60Co source or aged up to 100 days in 0.44 mol/L HNO3 before complexometric titration experiments. The obtained UV-Vis and Time-Resolved Laser Fluorescence Spectroscopy (TRLFS) results were compared with those of
fresh PTD solutions, in order to evaluate the impact of radiolysis and hydrolysis on metal-ligand complex formation. In accordance with the stability outlined by
previous studies, also the complexation capabilities resulted to be unaltered. These results further support PTD as a valid candidate for partitioning processes
I numeri della pandemia: istruzioni (e cautele) per l'uso
Get PDFThe contribution describes the role played by statistics in the management of the covid-19 pandemic in Italy. Data collection, choice of indicators, modelling are activities contributing to describe the infection spread, its impact on the population’s health and to define containment strategies. Diffusion time of an epidemic is short and fast responses are needed in every field: from medical doctors who must save lives, to scientists who must find solutions to erase the effects of the infection. For data analyzers, a compromise between data accuracy and fast results is inevitable. As a consequence, result indicators have a degree of uncertainty, which should be managed and communicated to policy makers and the general public. Usage of statistics during the pandemic will be illustrated: how data were collected, which indicators and statistical models were used to describe the phenomenon and how results were communicated to the various stakeholders. Criticisms, as well as good practices, will be explored