1,721,010 research outputs found
The Naples University 3 MV tandem accelerator
No full textThe 3 MV tandem accelerator of the Naples University is used for research activities and applications in many fields. At the beginning of operation (1977) the main utilization was in the field of nuclear physics. Later, the realization of new beam lines allowed the development of applied activities as radiocarbon dating, ion beam analysis, biophysics, ion implantation etc. At present, the availability of different ion sources and many improvements on the accelerator allow to run experiments in a wide range of subjects. An overview of the characteristics and major activities of the laboratory is presented
Applications of Accelerators and Radiation Sources in the Field of Space Research and Industry
No full textBeyond their important economic role in commercial communications, satellites in general are critical infrastructure because of the services they provide. In addition to satellites providing information which facilitates a better understanding of the space environment and improved performance of physics experiments, satellite observations are also used to actively monitor weather, geological processes, agricultural development and the evolution of natural and man-made hazards. Defence agencies depend on satellite services for communication in remote locations, as well as for reconnaissance and intelligence. Both commercial and government users rely on communication satellites to provide communication in the event of a disaster that damages ground-based communication systems, provide news, education and entertainment to remote areas and connect global businesses. The space radiation environment is an hazard to most satellite missions and can lead to extremely difficult operating conditions for all of the equipment travelling in space. Here, we first provide an overview of the main components of space radiation environment, followed by a description of the basic mechanism of the interaction of radiation with matter. This is followed by an introduction to the space radiation hardness assurance problem and the main effects of natural radiation to the microelectronics (total ionizing dose, displacement damage and the single-event effect and a description of how different effects occurring in the space can be tested in on-ground experiments by using particle accelerators and radiation sources. We also discuss standards and the recommended procedures to obtain reliable results
Measurement of differential cross sections in α+9Be elastic scattering
No full textWe report new experimen tal data concerning the elastic scattering of a-particles on 9Be nuclei in the bombarding energy region from 3.48 MeV up to 9.94 MeV, where a considerable lack of data exists in the literature. Data have been obtained at 110 , 135 , 150 , 160 backwar d polar angles suitable for IBA measurements. Excitation functions show various anomalies that can be linked to the presence of various excited states in the 13C compound nucleus. The present data have been compared with data reported in the literature, and an overall consistency is observed. The quality of the obtained excitation function at 160 has been benchmarked by performing EBS of a-particles on a thick and pure 9Be target at
two bombarding energies
Resonant elastic scattering of α particles on 9Be and cluster states in 13C
No full textWe discuss the preliminary results obtained by studying the +9Be elastic scattering at bombarding energies from 3.5 to 10 MeV. Experimental spectra show the presence of elastic and inelastic scattering phenomena. Elastic scattering excitation functions have been obtained at various angles; their shape is in good agreement with data at backward angles reported in the literature
Response of semi-insulating GaAs detectors to low energy protons
No full textThe performance of semi-insulating GaAs detectors, grown with the LEC technique, has been studied by irradiating
the Schottky diodes with 2 and 2.4 MeV monoenergetic protons in a pencil beam with sub-millimeter width (70 or
600 um). The beam was moved across the surface of the front (Schottky) contact, in order to investigate the uniformity of the detection characteristics over the sensitive area ofthe diodes, and to study the electric field behavior around the Schottky contact. For each scanning position, a pulse-height spectrum was measured. Then, the charge collected and the energy resolution were obtained as a function of the irradiation position both on the contact and outside it. The data show that
- the best spectroscopic response occurs for the beam with 70 um width,
- when the beam is incident onto the contact, the energy resolution is between 1% and 5%, and the variation ofthe
charge collected, for different irradiation position, is less than 30%,
- when the beam is incident onto the border of the contact (substrate is irradiated), the spectrum is degraded and no
clear peak is present,
- collection of charge still occurs at distances up to about 500 um from the border of the Schottky contact (for a pixel
size of 200 um), or up to about 200 um (for a pixel diameter of 3 mm),
- saturation ofthe curve collected charge vs. reverse bias voltage occurs at about 100 V for both 2 MeV
(range=32 um) and 2.4 MeV protons (range=41 um)
In Vitro effects of exposure to radiofrequency on DNA damage induced by high-LET ionising radiation.
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The versilian transgression in the Volturno river plain (Campania, southern Italy): palaeoenvironmental history and chronological data.
No full textIn order to reconstruct the Holocene evolution of Volturno river coastal plain, a geomorphological survey was carried out and three boreholes (A, B and C) were drilled in the southern sector of the area. Further stratigraphical data were available from pre-existing boreholes from scattered locations on the plain. For samples obtained from borehole A, B and C, ostracod analysis, lithostratigraphical observations and AMS 14C dating were carried out. The Holocene deposits outcrop along the coastal beach-ridges of the strand plain, and in the flat back-barrier depression, the northern area of which is partially occupied by the composite and raised meander belt of the Volturno river. These deposits lie on the subaerial erosional landscape carved in the Campanian Ignimbrite formation (the latter being 42 to 27 ka BP in age) during the last glacio-eustatic low stand. The wedge-shaped sedimentary body (up to 30 m thick) is composed of sands and silts near the coast (penetrated by core A) and of clays, peats and silts (cores B and C) in the inner part of the plain. Both the sedimentary reconstructions carried out on the well-logs and the three dimensional arrangement of the Holocene sedimentary units allowed for both the reconstruction of the sediment geometry and the assessment of the major paleonvironmental changes occurred in the area as a result of relative sea-level changes. The lower part of the Holocene succession is represented by a transgressive barrier-lagoon system, the onset of which is marked by beach sands, recognized in borehole A at a depth of 23-22 m b.s.l. The inferred age for this marine layer is about 10 ka BP. Due to the persistence of sea-level rise, the barrier complex shifted inland, up to a maximum distance of 1.5 km from the modern position, and the lagoon depression also migrated inland. The subsequent late Holocene environmental history was characterized by a regression phase dominated by deposition, which resulted in the progradation of the paleo-shoreline to its modern position. This progradation is identified by up to 10 m of Holocene deposits composed of dune sands (exposed across the area), which pass downwards to sands of shore-face and transition zone. Although no precise chronological constraints are available for the 14C dates obtained from peaty
Influenza del segnale UMTS (1.95 GHz) su danno citogenetico acuto ed instabilità genomica indotti in vitro da radiazione ionizzante ad alto LET.
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