Micro‐PIXE determination of Zr in rutile: an application to geothermometry of high‐P rocks from the western Alps (Italy)

AbstractThe Western Alps of Northern Italy mostly consist of lithotectonic units which re‐crystallised and were metamorphosed at high depth in a subduction zone. During their exhumation to shallow crustal levels, however, the high‐pressure (high‐P) mineral assemblages were pervasively re‐equilibrated under low‐pressure (low‐P) conditions, making difficult to estimate the metamorphic thermal peak.Rutile [TiO2] is a typical high‐P mineral, occurring as relict phase in low‐P re‐equilibrated metamorphic rocks. Recent studies suggest that, in thermodynamic systems buffered by the occurrence of quartz and zircon in the rock, Zr content in rutile is a temperature–dependent function that can be modelled quantitatively.An application of rutile Zr‐geothermometer to continental and oceanic rocks of the Western Alps, pervasively re‐equilibrated under low‐P conditions, is presented.The selected rutile crystals were analysed by PIXE using a microbeam set‐up at the LABEC laboratory of INFN in Florence. The PIXE spectra and maps were processed by Geopixe software package. Micro‐PIXE analyses allowed determining the concentration and the distribution of Zr.Results obtained by applying the rutile Zr‐geothermometer gave a more precise indication about the temperatures of the metamorphic conditions suffered by Alpine metamorphic rocks with respect to phase relations and conventional geothermometry, showing that determination of Zr concentration by micro‐PIXE technique is a useful tool to reconstruct metamorphic events.The continental units, outcropping in separate zones of Western Alps, show two slightly different thermal peaks (Tmean = 530 ± 10 °C and Tmean = 555 ± 10 °C) for the same metamorphic event. The oceanic units provide Tmean estimates of 575 ± 10 °C slightly higher than the continental units. Copyright © 2008 John Wiley & Sons, Ltd

The ionoluminescence apparatus at the LABEC external microbeam facility

Abstract In this paper, we describe the main features of the ionoluminescence (IL) apparatus recently installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC Laboratory in Firenze. The peculiarity of this IL set-up resides in the fact that the light produced by the ion irradiation of the specimen is collected by a bifurcated optical fiber, so that photons are shunted both to a CCD spectrometer, working in the 200–900 nm wavelength range, and to a photomultiplier (PMT). The accurate focusing of the optical system allows high photon collection efficiency and this results in rapid acquisition of luminescence spectra with low ion currents on luminescent materials; simultaneously, luminescence maps with a spatial resolution of 10 μm can be acquired through the synchronization of PMT photon detection with the position of the scanning focused ion beam. An optical filter with a narrow passband facing the photomultiplier allows chromatic selectivity of the luminescence centres. The IL apparatus is synergistically integrated into the existing set-up for ion beam analyses (IBA). The upgraded system permits simultaneous IL and PIXE/PIGE/BS measurements. With our integrated system, we have been studying raw lapis lazuli samples of different known origins and precious lapis lazuli artworks of the Collezione Medicea of Museum of Natural History, University of Firenze, aiming at characterising their composition and provenance

Modification of the electrical and optical Properties of Single Crystal Diamond with Focused MeV Ion Beams

AbstractIn this paper an overview is given on recent results obtained in the framework of an Italian/Croatian collaboration aimed to explore the potential of techniques based on focused MeV ion beams to locally modify the structural, electrical and optical features of diamond.Experiments were carried out using light (H, He, C) ion beams with energies of the order of MeV, focused to micrometer-size spot and raster scanned onto the surface of monocrystalline (IIa or Ib) diamond samples. Different energies, ion species and fluences were used, in conjunction with variable thickness masks and post annealing processes, to define three-dimensional structures in diamond, whose electrical/optical/structural properties have been suitably characterized. Finite element numerical methods have been employed in the modeling of the material modification and in device design

The Role of PIXE and XRF in Heritage Science: The INFN-CHNet LABEC Experience

Analytical techniques play a fundamental role in heritage science. Among them, Particle Induced X-ray Emission (PIXE) and X-ray Fluorescence (XRF) techniques are widely used in many laboratories for elemental composition analysis. Although they are well-established, a strong effort is put on their upgrade, making them suitable for more and more applications. Over the years, at the INFN-LABEC (the laboratory of nuclear techniques for the environment and cultural heritage of the Italian National Institute of Nuclear Physics), the INFN-CHNet group, the network devoted to cultural heritage, has carried out many technological improvements to the PIXE and XRF set-ups for the analysis of works of art and archaeological finds. Among the many, we recall here the scanning external microbeam facility at the TANDEM accelerator and the MA-XRF scanner. The two instruments have shown complementary features: the former permits quantitative analysis of elements heavier than sodium, which is not possible with the latter in most of the case studies. On the contrary, the scanner has the undeniable advantage of portability, allowing it to work in situ. In this framework of technological developments in heritage science, INFN, CERN, and OPD are jointly carrying on the MACHINA (Movable Accelerator for Cultural Heritage In-situ Non-destructive Analysis) project for on-site Ion Beam Analysis (IBA) studies on cultural heritage

La restauración del Retrato Trivulzio de Antonello da Messina

El artículo presenta la intervención llevada a cabo en 2006 sobre el Retrato de hombre de Antonello da Messina, que pertenece a las colecciones del Museo Cívico de Arte Antiguo del Palacio Madame. The article presents the intervention carried out in 2006 about the Portrait of a man of Antonello da Messina, which belongs to the collections of the Civic Museum of Ancient Art of the Madame Palace.El artículo presenta la intervención llevada a cabo en 2006 sobre el Retrato de hombre de Antonello da Messina, que pertenece a las colecciones del Museo Cívico de Arte Antiguo del Palacio Madame.&nbsp

Cultura alta o cultura bassa? Un’indagine sui consumi 7 culturali degli immigrati in Italia

No abstract availabl

Cultura alta o cultura bassa? Un’indagine sui consumi culturali degli immigrati in Italia

Le industrie culturali e creative rientrano tra i settori che hanno mag- giormente risentito dell’influenza dei nuovi paradigmi sociali introdotti dalla globalizzazione, come, ad esempio, la società multiculturale. Negli ultimi decenni, le istituzioni locali, gli enti pubblici e privati, i luoghi della cultura hanno dovuto ripensare il proprio posizionamento strategico, tenen- do conto della crescente presenza di consumatori di altre lingue e culture e rinnovando le proprie politiche di marketing in chiave interculturale. La partecipazione ad attività artistico-culturali, infatti, è stata ritenuta per molti anni una prerogativa delle classi sociali più alte e, specificata- mente, della popolazione nativa di un determinato luogo. In quest’ottica, si riteneva che le minoranze etniche avessero meno probabilità di partecipare ad attività artistiche e culturali rispetto alle loro controparti di maggio- ranza (Chan, Goldthorpe, 2007). La variabile economica giocava un ruolo chiave in queste teorie: le minoranze etniche, infatti, erano associate a una posizione economica inferiore rispetto ai nativi (Buraimo et al., 2011), che ne comportava l’esclusione dalle attività culturali cosiddette alte (museo, teatro, ecc.)