Groupe PACA -Former les usagers : enjeux et écueils

Alors que l’ABF consacrait un dossier sur la formation des usagers (BIBLIOthèque(s) Usages-Usagers), le groupe PACA organisait une journée d’étude en octobre. La présentation des expériences menées en BM et en BU, à Toulon, Nice, Aix et Marseille, permit de dégager de nouvelles orientations. Bilan

Response of CdWO4 crystal scintillator for few MeV ions and low energy electrons

The response of a CdWO4 crystal scintillator to protons, alpha particles, Li, C, O and Ti ions with energies in the range 1 - 10 MeV was measured. The non-proportionality of CdWO4 for low energy electrons (4 - 110 keV) was studied with the Compton Coincidence Technique. The energy dependence of the quenching factors for ions and the relative light yield for low energy electrons was calculated using a semi-empirical approach. Pulse-shape discrimination ability between gamma quanta, protons, alpha particles and ions was investigated.Comment: 20 pages, 8 figs, accepted in Nucl. Instrum. Meth.

Physics with the accelerators at Arcetri. A short chronicle dedicated to Tito Fazzini who was one of its leading protagonists

A general overview of the period from 1960 to 2000, during which two electrostatic accelerators were in operation at Arcetri. Also by implementing novel devices, these accelerators were used to carry out studies on nuclear structure, parity violation and nuclear reactions.Si ripercorre per grandi linee il periodo dal 1960 al 2000 in cui sono stati operativi in Arcetri due acceleratori elettrostatici con i quali, anche attuando sofisticati accorgimenti tecnici, sono stati condotti studi di struttura nucleare, di violazione di parità e di reazioni nucleari

Spatial Resolution of Double-Sided Silicon Microstrip Detectors for the PAMELA Apparatus

The PAMELA apparatus has been assembled and it is ready to be launched in a satellite mission to study mainly the antiparticle component of cosmic rays. In this paper the performances obtained for the silicon microstrip detectors used in the magnetic spectrometer are presented. This subdetector reconstructs the curvature of a charged particle in the magnetic field produced by a permanent magnet and consequently determines momentum and charge sign, thanks to a very good accuracy in the position measurements (better than 3 um in the bending coordinate). A complete simulation of the silicon microstrip detectors has been developed in order to investigate in great detail the sensor's characteristics. Simulated events have been then compared with data gathered from minimum ionizing particle (MIP) beams during the last years in order to tune free parameters of the simulation. Finally some either widely used or original position finding algorithms, designed for such kind of detectors, have been applied to events with different incidence angles. As a result of the analysis, a method of impact point reconstruction can be chosen, depending on both the particle's incidence angle and the cluster multiplicity, so as to maximize the capability of the spectrometer in antiparticle tagging.Comment: 28 pages, 18 figures, submitted to Nuclear Instruments and Methods in Physics Research

Native NIR-emitting single colour centres in CVD diamond

Single-photon sources are a fundamental element for developing quantum technologies, and sources based on colour centres in diamonds are among the most promising candidates. The well-known NV centres are characterized by several limitations, thus few other defects have recently been considered. In the present work, we characterize in detail native efficient single colour centres emitting in the near infra-red in both standard IIa single-crystal and electronic-grade polycrystalline commercial CVD diamond samples. In the former case, a high-temperature annealing process in vacuum is necessary to induce the formation/activation of luminescent centres with good emission properties, while in the latter case the annealing process has marginal beneficial effects on the number and performances of native centres in commercially available samples. Although displaying significant variability in several photo physical properties (emission wavelength, emission rate instabilities, saturation behaviours), these centres generally display appealing photophysical properties for applications as single photon sources: short lifetimes, high emission rates and strongly polarized light. The native centres are tentatively attributed to impurities incorporated in the diamond crystal during the CVD growth of high-quality type IIa samples, and offer promising perspectives in diamond-based photonics.Comment: 27 pages, 10 figures. Submitted to "New Journal of Phsyics", NJP-100003.R

Time measurements by means of digital sampling techniques: a study case of 100 ps FWHM time resolution with a 100 MSample/s, 12 bit digitizer

Abstract An application of digital sampling techniques is presented which can simplify experiments involving sub-nanosecond time-mark determinations and energy measurements with nuclear detectors, used for Pulse Shape Analysis and Time of Flight measurements in heavy ion experiments. The basic principles of the method are discussed as well as the main parameters that influence the accuracy of the measurements. The method allows to obtain both time and amplitude information with an electronic chain simply consisting of a charge preamplifier and a fast high resolution ADC (in the present application: 100 MSample/s , 12 bit ) coupled to an efficient on-line software. In particular an accurate Time of Flight information can be obtained by mixing a beam related time signal with the output of the preamplifier. Examples of this technique applied to Silicon detectors in heavy-ions experiments involving particle identification via Pulse Shape analysis and Time of Flight measurements are presented. The system is suited for applications to large detector arrays and to different kinds of detectors

Dispositivo di calibrazione per il digitalizzatore della Grotta Gigante

aggiornamento dispositivo di calibrazione per l'acquisizione digitale dati dei pendoli della grotta gigant

Energy and angular momentum sharing in dissipative collisions

Primary and secondary masses of heavy reaction products have been deduced from kinematics and E-ToF measurements, respectively, for the direct and reverse collisions of 93Nb and 116Sn at 25 AMeV. Light charged particles have also been measured in coincidence with the heavy fragments. Direct experimental evidence of the correlation of energy-sharing with net mass transfer has been found using the information from both the heavy fragments and the light charged particles. The ratio of Hydrogen and Helium multiplicities points to a further correlation of angular momentum sharing with net mass transfer.Comment: 21 pages, 20 figures. Submitted to European Physics Journal

Mapping with Macro X-ray Fluorescence Scanning of Raffaello's Portrait of Leo X

Raffaello is renowned as one of the Old Renaissance Masters and his paintings and painting technique are famous for the details and naturality of the characters. Raffaello is famous in particular for the then-new technique of oil painting, which he mastered and perfected. On the occasion of the 500th anniversary of the death of Raffaello (2020), there was a large exhibition at the Scuderie del Quirinale in Rome, where many paintings and drawings by the Old Master were on show. One of these paintings was the portrait of Leo X with two cardinals belonging to the collection of the Uffizi galleries in Florence. Before going to Rome, the painting underwent conservation treatments at the Opificio delle Pietre Dure, where a comprehensive diagnostic campaign was carried out with the aim of understanding the painting materials and technique of the Old Master. In this paper, the results of macro X-ray fluorescence (MA-XRF) analysis, carried out exploiting the instrument developed by INFN-CHNet, are shown. Among the results, "bismuth black" and the likely use of glass powders in lakes are discussed