Search results for " nuclear"
showing 10 items of 11776 documents
A GEM-TPC in twin configuration for the Super-FRS tracking of heavy ions at FAIR
2018
The GEM-TPC [1] described herein will be part of the standard beam-diagnostics equipment of the Super-FRS [2] . This chamber will provide tracking information for particle identification at rates up to 1 MHz on an event-by-event basis. The key requirements of operation for these chambers are: close to 100% tracking efficiency under conditions of high counting rate, spatial resolution below 1 mm and a superb large dynamic range covering projectiles from Z=1 up to Z=92. The current prototype consists of two GEM-TPCs inside a single vessel, which are operating independently and have electrical drift fields in opposite directions. The twin configuration is done by flipping one of the GEM-TPCs o…
Prevalencia y factores de desgaste profesional en radiólogos durante la pandemia COVID-19
2022
Antecedentes: La epidemia por coronavirus 2019 (COVID-19) se ha extendido por todo el mundo desde principios de 2020, sometiendo a los profesionales sanitarios a una sobrecarga laboral ya un mayor nivel de estrés físico y emocional. Objetivos: El objetivo de este estudio es determinar la prevalencia de desgaste profesional y sus posibles factores asociados en los radiólogos españoles durante la COVID-19, y su comparación con la situación previa a la pandemia. Métodos: Estudio observacional realizado entre los meses de abril y agosto de 2020 (durante la pandemia) mediante una encuesta en línea. Se obtuvieron un total de 150 respuestas. Se recopiló y comparó la información demográfica y labor…
First observation and study of the K± → π±π0e+e− decay
2018
The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.
Rare beta decays and the spectrum-shape method
2017
This is a thesis consisting of seven publications and an introductory part on theoretical studies on rare single beta decays. Firstly, the theoretical framework is applied to the computation of partial half-lives for few selected cases of rare single beta-decay transitions. This includes the study on a possible ultra-low-Q-value decay branch of 115Cd as well as the highly forbidden beta decays of 48Ca and 50V. The double magic 48Ca is one of the few experimentally verified nuclei that decay via the two-neutrino mode of double beta decay. A theoretical study on the single beta-decay branches was used to inspect the competition between the single and double beta-decay channels. In the case of…
Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering Determined by the OLYMPUS Experiment
2017
The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, $R_{2\gamma}$, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of $\approx 20\degree$ to $80\degree$. The relative luminosity between the two beam species was mo…
Structured reporting of rectal cancer staging and restaging: A consensus proposal
2021
Background: Structured reporting (SR) in oncologic imaging is becoming necessary and has recently been recognized by major scientific societies. The aim of this study was to build MRI-based structured reports for rectal cancer (RC) staging and restaging in order to provide clinicians all critical tumor information. Materials and Methods: A panel of radiologist experts in abdominal imaging, called the members of the Italian Society of Medical and Interventional Radiology, was established. The modified Delphi process was used to build the SR and to assess the level of agreement in all sections. The Cronbach’s alpha (Cα) correlation coefficient was used to assess the internal consistency of ea…
PROVE ED ESPERIMENTI DI VERIFICA DELLA SICUREZZA DEL REATTORE NUCLEARE DI RICERCA AGN-201 “COSTANZA”
2011
The “Zero Power” Nuclear Reactor AGN-201 “Costanza” available at Nuclear Engineering Department of Palermo University is a valuable tool for educational purpose and research. Besides being a useful tool for training of operators, without the time period limits on start-up and shut-down of the larger reactors, it allows the study of some phenomena regarding nuclear reactor physics, applied neutronics, neutron dosimetry, nuclear measurements as well as testing of nuclear instrumentation and methods. The experience of work and the obtained results highlight the simplicity of AGN-201 reactor control, its intrinsic safety and its overall versatility in various fields of Nuclear Engineering.
The Experimental Study of Heat Waste Conversion into Useful Electric Power
2009
This paper presents the practical results ofthe design solutions, executing and experimentaltesting of a prototype model of o thermoelectricgenerator, based on the conversion of residualthermical energy into electric power, by improving theSeebeck effect. To this purpose, high performancethermoelectric modules have been used, taken from therecent production of the American Corporation Hi-ZTechnology. The prototype thermoelectric generatorbuilt for a demonstrative purposes has got the lowefficiency category. The results taken from the testsand experimental measurements have showntheimportance of the constructive solution of materialsand technologies that have been used. These resultsdirect t…
RELAP5 simulation of two-phase flow experiments in vertical helical tubes
2010
In the framework of the studies concerning the thermalfluid dynamic phenomena in helicoidal pipes of the innovative nuclear reactor IRIS steam generators, the Department of Nuclear Engineering of the University of Palermo in collaboration with the Politecnico di Torino Department of Energetics has been engaged in a work aimed to adapt, by implementing new suitable models, RELAP5/mod3.2.2β code to simulate the thermalfluid-dynamics and geometries such as the ones involved in helicoidal pipes. In fact this code is based on one-dimensional thermal-hydraulic relationships and presents limitations to model complicated geometry such as helicoidal pipes. Therefore the code was improved with additi…
Dangerous Effects Induced on Power MOSFETs by Terrestrial Neutrons
2013
This paper investigates the effects that terrestrial neutrons can induce on power MOSFETs when they are biased during their normal working conditions especially in inverters for photovoltaic applications. After a brief review of power MOSFETs failure phenomena caused by neutron irradiation (with emphasis on so called “Single Event Effects” (SEE)), the results of an accelerated test performed with the Am-Be source at the University of Palermo are discussed.