170,958 research outputs found
Study and development of high release refractory materials for the SPES project
No full textThroughout the last century, theoretical and experimental research made by the international nuclear physicists community has led to important advancement in the knowledge of the mechanisms that govern the behavior and stability of the nuclei. The technological improvements necessary to support this research has often opened the way to new applications in other field of science and industry which directly reflects in our common life experience.
Nowadays, Europe is becoming more and more a leader in both theoretical and experimental nuclear physics, as testified by the presence on its territory of several institutes and laboratories dedicated to this field of research, like CERN (Organisation Européenne pour la Recherche Nucléaire), the world’s largest particle physics laboratory. Italy, represented mainly by INFN (Istituto Nazionale di Fisica Nucleare), is one of the main members of this community.
One of the most important projects supported by INFN is SPES (Selective Production of Exotic Species), which aim is to develop a facility for the production of radioactive ion beams (RIBs) in one of the four national laboratories of INFN, LNL (Laboratori Nazionali di Legnaro).
The facility is designed to produce and deliver to users both proton-rich and neutron-rich nuclei (range of mass 80-160 amu) to be used for nuclear physics research, as well as other applications in different fields of science. The generation of the aforementioned isotopes will occur inside a properly designed target, which represents the core of the whole project. The choice of the proper material for the target, both in terms of composition and properties, is of vital importance in determining the quantity and type of the produced isotopes.
In this work, the synthesis and characterization of different types of target materials are presented. The results of experimental tests performed on some of the produced materials, in configurations very similar to those intended for the final SPES facility are also reported.
Chapter 1 gives a general overview of the SPES project and its context whereas chapter 2 introduces the main topics related to the on-line behavior of the SPES target, relative to both its layout and to the properties of the material constituting it. Chapter 3 is focused on uranium carbide, which will be used at SPES to produce neutron-rich isotopes; after a description of its main physicochemical properties, the results of two on-line tests performed on target prototypes made of this material is reported and discussed into detail. In chapter 4 the synthesis methods and release-related properties of two potential materials to be used as SPES targets for the production of proton-rich isotopes, boron and lanthanum carbides, are presente
John Ruskin as Slade Professor of Art at Oxford University
No full textProblem: During his Professorship, Ruskin at Oxford inaugurated his program of socialized Art, which he later developed broadly, and for which he is known in history. |From birth to manhood, John Ruskin possessed an animating love for Art in Nature. Specifically, his native fondness for sincere Beauty and his acquired thirst for Truth constituted a definite progression through his youth toward a mature philosophy. This Nature wisdom-- knowledge of how to live happily and dutifully—Ruskin yearned to work out for the amelioration of humanity in the confused society known as the Victorian Age. When appointed Slade Professor of Art at Oxford University, he realized an opportunity for the fulfillment of his desire; and, in turn, this undertaking enlarged his genius to the utmost of its possibilities.ProQuest Traditional Publishing Optio
The RIB production target for the SPES project
No full textFacilities making use of the Isotope Separator On-Line (ISOL) method for the production of Radioactive Ion Beams (RIB) attract interest because they can be used for nuclear structure and reaction studies, astrophysics research and interdisciplinary applications. The ISOL technique is based on the fast release of the nuclear reaction products from the chosen target material together with their ionization into short-lived nuclei beams. Within this context, the SPES (Selective Production of Exotic Species) facility is now under construction in Italy at INFN-LNL (Istituto Nazionale di Fisica Nucleare — Laboratori Nazionali di Legnaro). The SPES facility will produce RIBs mainly from n-rich isotopes obtained by a 40 MeV cyclotron proton beam (200 μA) directly impinging on a uranium carbide multi-foil fission target. The aim of this work is to describe and update, from a comprehensive point of view, the most important results obtained by the analysis of the on-line behavior of the SPES production target assembly. In particular an improved target configuration has been studied by comparing different codes and physics models: the thermal analyses and the isotope production are re-evaluated. Then some consequent radioprotection aspects, which are essential for the installation and operation of the facility, are presented. © 2015, SIF, Springer-Verlag Berlin Heidelberg
Personificazioni e monete. Il caso di Spes/Elpís
No full textIl contributo analizza il soggetto monetale di Spes e di Elpis (in ambito greco), dal punto di vista iconografico, ideologico, simbolico. Illustra poi le due emissioni di Claudio con la prima raffigurazione monetale della dea, cercando di definire i motivi di questaa innovazione iconografica. Sono infine presentate otto monete della Collezione numismatica dell'Università Cattolica di Milano con raffigurazione di Spes o di Elpis
The SPES Direct Target Project at LNL
No full textThe SPES Direct Target Project at the Laboratori Nazionali di Legnaro (Italy), devoted to the construction of a Radioactive Ion Beam (RIB) Facility within the framework of the new European RIB panorama, is presented. An innovative configuration for the SPES Project, for the production of neutron-rich exotic nuclei, proposes the use of a primary proton beam (40 MeV, 0.2 mA), directly impinging on a large Multi-Slice Uranium Carbide Direct Target. The goal is to reach a high number of fission products (up to 1013 fissions/s), still keeping a quite low power deposition inside the target. The description of the overall facility together with details on the Direct Target configuration is presented. Thermo-mechanical calculations, material preparation and characterisation, effusion--diffusion model predictions for the estimation of the release time and total release fraction for different life times and isotopes will be discussed. Finally, a scaled (1:5) prototype of the Target System built to be tested and compared under existing proton beam facilities, will be described
Crosslinked SPES-SPPSU membranes for high temperature PEMFCs
No full textHighly sulfonated polyethersulfone (SPES; lone exchange capacity = 3.2 meq/g) and polyphenylsulfone (SPPSU; ion exchange capacity = 3.2 meq/g) were synthesized. To get high thermal and chemical stability, a blend membrane was prepared by the composite of SPES and SPPSU. The SPES-SPPSU blend membrane after the annealing treatment at 180 degrees C was stable in water and other organic solvents, and the thermal stability was also more increased than that of pristine SPES and SPPSU polymers due to the crosslinking formation among SPES and SPPSU. The maximum conductivity of 0.12 S/cm was obtained at the temperature of 140 degrees C and RH 90%. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved
Calculations and First Results Obtained with a SiC prototype of the SPES direct target
No full textIn the framework of the SPES project at LNL [A. Bracco, A. Pisent (Ed.), REP 181/02, LNL-INFN, 2002], the realization of a direct ISOL Target for a mid-term radioactive ion beam facility is in progress. Using a primary proton beam of energy 40 MeV and intensity 0.2 mA, a high number of fission products will be obtained in the SPES multi-foil uranium carbide target, keeping a low power density deposition in the refractory matrix [A. Andrighetto, S. Cevolani, C. Petrovich, Eur. Phys J. A 25 (2005) 41]. The exotic species produced by Uranium fission in the target are collected in the ion source after the diffusion and the effusion processes. When short lived isotopes are produced it is very important to optimize the release properties of the target. To this purpose the RIBO code (radioactive ion beam optimiser) [M. Santana Leitner, A Monte Carlo Code to Optimize the Production of Radioactive Ion Beams by the ISOL Technique, PhD. Thesis, UPC-ETSEIB/CERN] has been used in order to estimate the target release efficiency for some neutron-rich nuclei. A SiC prototype of the target was recently produced at LNL and tested at ORNL using a 42 MeV proton beam. The yield of some aluminum isotopes was measured as a function of the target temperature. Some preliminary results of the data analysis will be presented
Crosslinked SPES-SPPSU membranes for high temperature PEMFCs
No full textHighly sulfonated polyethersulfone (SPES; lone exchange capacity = 3.2 meq/g) and polyphenylsulfone (SPPSU; ion exchange capacity = 3.2 meq/g) were synthesized. To get high thermal and chemical stability, a blend membrane was prepared by the composite of SPES and SPPSU. The SPES-SPPSU blend membrane after the annealing treatment at 180 degrees C was stable in water and other organic solvents, and the thermal stability was also more increased than that of pristine SPES and SPPSU polymers due to the crosslinking formation among SPES and SPPSU. The maximum conductivity of 0.12 S/cm was obtained at the temperature of 140 degrees C and RH 90%. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved
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