Search results for " ambientali"

Direct Measurement of Mammographic X-Ray Spectra with a Digital CdTe Detection System

2012

In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1–30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled and digitized by a 14-bit, 100 MHz ADC. We show the results of the characterization of the detection system both at low and high photon counting rates by using monoenergetic X-ray sources and a nonclinical X-ray tube. The detection system exhibits excellent performance up to 830 kcps with an energy resolution of 4.5% FWHM at 22.1 keV. Direct measurements of clinical molybdenum X-ray spectra were carried out by using a pinhole…

Cambiamenti climatici e migrazioni forzate. Limiti e prospettive dell'attuale sistema di protezione dei diritti fondamentali.

Trans-cranial Magnetic Resonance-guided Focused UltraSound (tcMRgFUS) system integrated with a 1.5T: an SNR study on DQA phantoms

2018

Background: In recent years transcranial Magnetic Resonance-guided Focused Ultrasound Surgery (tcMRgFUS) treatments have been performed only using 3T units. Since following some internal analysis, planning images obtained using a 1.5T MRI’s body RF coil (as usually done with 3T systems) showed generally reasonable quality in terms of anatomy visualization and SNR but thermal images noise was above acceptable standard for treatments, a dedicated 2-channels head coil was developed (InSightec Ltd.) to ensure an adequate signal-to-noise ratio (SNR). Hence, we present the imaging protocol and the technological methods successfully used with the world-first installation of a certified tcMRgFUS sy…

Anagraphical relationships and crime specialization within Cosa Nostra

2021

Abstract The aim of the present work is to investigate the relationships established within Cosa Nostra, by making use of networks and complex-systems methods. The analysis is performed at three different levels, that is, individuals, groups within mafia syndicates, and relationships amongst mafia syndicates. The reported empirical analysis is based on the criminal records of 632 affiliates to Cosa Nostra selected from a set of 125 judgements emitted by the Palermo courts from 2000 to 2014. According to the criminal records of the Palermo Prosecutor Office, such a dataset includes approximately 10% of the whole population of Cosa Nostra affiliates in western Sicily. Furthermore, the vital s…

The gas chromatography/mass spectrometry can be used for dose estimation in irradiated pork

2009

Abstract Food safety can be improved using ionizing radiation to reduce food spoilage and to extend its shelf life. The gas chromatography/mass spectrometry (GC/MS) has been validated by the European Community as a powerful method to identify irradiated food containing fat. The preliminary goals of our research were: (i) to set up this method, based on the detection of radiation induced 2-dodecylcyclobutanones (2-DCB) in pork muscle samples and (ii) to check the microbiological efficacy of the treatment. The main objective was to render the GC/MS a quantitative technique for dose estimation, through the measurement of the 2-DCB concentration in the irradiated sample. Our results show that t…

Six-dimensional measurements of trains of high brightness electron bunches

2015

Trains of ultrashort electron pulses with THz repetition rate, so-called comblike beams, are assuming an ever growing interest in plasma-based acceleration. In particle-driven plasma wakefield acceleration (PWFA), a train of driver bunches with separation of the order of plasma wavelength, i.e., 300 μm, resonantly excites a plasma wake, which accelerates a trailing witness bunch, injected at the accelerating phase. Comblike beams have great potentialities in different fields of applications. In particular, radiation sources, such as free-electron lasers and THz radiation, take advantage from the possibility to tailor electron beams modulated both in time and energy, to customize emission ba…

Dating of Brazilian shells through electron paramagnetic resonance

2019

In the present work we report dating procedure of these shells by using the electron paramagnetic resonance. The first step of the analysis was the definition of the optimal procedure for sample preparation. At this aim the analysis of the sample composition was carried out by X-ray fluorescence (XRF) measurements and an accurate analysis was study on the effect of the chemical etching with varying typology and concentration of acid to be used for removing the external layer of shells which are affected by alpha particles.

ELECTRON SPIN RELAXATION PROCESS IN SILICON CRYSTALS

2014

Recently, electrical injection of spin polarization in n-type and p-type silicon has been experimentally carried out up to room-temperature. Despite of these preliminary but promising experimental results, a comprehensive theoretical framework concerning the influence of transport conditions on the phonon-induced spin depolarization process in silicon structures, in a wide range of values of temperature, doping concentration and amplitude of external fields, is still in a developing stage. In order to elucidate the electron transport and spin dynamics of conduction electrons in lightly doped n-type Si crystals we have performed semiclassical multiparticle Monte Carlo simulations and numeric…

Monte Carlo Simulation of Spin Relaxation of Conduction Electrons in Silicon

2014

Recently, electrical injection of spin polarization in n-type and p-type silicon up to room-temperature has been experimental- ly carried out. Despite of these promising experimental results, a comprehensive theoretical framework concerning the influence of transport conditions on the spin depolarization process in silicon structures, in a wide range of values of temperature, doping concentration and amplitude of external fields, is still in a developing stage. In this contribution we use a semiclassical multiparti- cle Monte Carlo approach to simulate the electron transport and spin dynamics in lightly doped n-type Si crystals and numerically calculate the spin lifetimes of drifting electr…

HOT-ELECTRON NOISE FEATURES IN SILICON CRYSTALS OPERATING UNDER PERIODIC SIGNALS

2014

We study the intrinsic noise in n-type Si crystals operating under high-frequency periodic electric fields. To simulate the dy- namics of electrons in the bulk, by taking into account the main details of band structure, scattering processes, as well as heating effects, a Monte Carlo approach is used. The noise properties are investigated by computing the velocity fluctuations correlation function, its spectral density, and the total noise power for different values of the amplitude and frequency of the driving field. We show that the noise features are significantly affected by the electric field amplitude and frequency and discuss their peculiari- ties in comparison with those exhibited in…