Realisation and characterisation of Cu-based references for neutron imaging calibration purposes and first results

The long-term purpose of this study is to assess the capabilities of the new Neutron Imaging beamline developed at the LENA facility of Pavia (Italy) for the characterisation of bronze artefacts. In this preliminary work, a set of Cu-based reference alloys has been produced and analysed in order to test and calibrate the facility. The first step involved the production of Cu-based alloys with chemical composition and microstructure similar to ancient artefacts. The chemical composition of the reference alloys was analysed by Optical Emission Spectroscopy. Secondly, some samples were artificially patinated with different chemical treatments obtaining an artificial corrosion products layer comparable to natural corrosion. X-Ray Diffraction, Scanning Electron Microscopy and Raman Spectroscopy have been used to characterise the corrosion patina. The main corrosion products on sulphate-induced patina are cuprite and brochantite, whereas atacamite and clinoatacamite were detected on chloride-induced patinas. Finally, preliminary Neutron Imaging measurements were performed on a first set of coated and uncoated specimens in order to try to correlate the neutrons attenuation coefficients with the chemical compositions with promising results

A new method for the determination of very small Γγ partial widths

We present a new method for the measurement of very small Γγ partial width that is important for the synthesis of elements in astrophysics. The method is based on the simultaneous detection of scattered beam, residual nucleus and decay γ rays. This method is optimized for the use of the CHIMERA detector at LNS. Experimental details are described

A new method for the determination of very small Γ γ

We present a new method for the measurement of very small Γγ partial width that is important for the synthesis of elements in astrophysics. The method is based on the simultaneous detection of scattered beam, residual nucleus and decay γ rays. This method is optimized for the use of the CHIMERA detector at LNS. Experimental details are described

Studio di sistemi nucleari prodotti con reazioni tra ioni pesanti tramite la risonanza gigante di dipolo

Dottorato di ricerca in fisica. 6. ciclo. A.a. 1992-93. Relatore P. Blasi. M. Rosa-ClotConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Imaging study of Raffaello's "La Muta" by a portable XRF spectrometer

In studies of Cultural Heritage, there is a growing demand for methods of material investigation. X-Ray Fluorescence (XRF) analyses have proven to be essential tools in these material studies. The XRF scanning spectrometer, developed at the LABEC laboratory in Florence, can perform both elemental mapping, on areas up to 20×20cm2, and single spot analyses. Thanks to our close and long lasting collaboration with the Opificio delle Pietre Dure in Florence, one of the most prestigious restoration centers in the world, we had the opportunity to use the new XRF spectrometer in analyzing the painting "La Muta" of Raffaello Sanzio, one of the "Old Masters" of the Italian Renaissance.Beyond identification of the painting palette, the XRF study further allowed for structural analysis in cases where single spot XRF measurements would not be adequate. For example, the new system allowed us to deduce Raffaello's use of bone black pigment and to analyze various instances of "pentimenti" (underlying image in a painting, evidence of revision by the artist)

Light emission from color centers in phosphorus-doped diamond

Light emission from color centers in diamond is being extensively investigated for developing, among other quantum devices, single-photon sources operating at room temperature. By doping diamond with phosphorus, one obtains an n-type semiconductor, which can be exploited for the electrical excitation of color centers. Here, we discuss the optical properties of color centers in phosphorus-doped diamond, especially the silicon-vacancy center, presenting the single-photon emission characteristics and the temperature dependence aiming for electroluminescent single-photon emitting devices