23 research outputs found

    Fisica dell'accrescimento

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    L'accrescimento √® un fenomeno di fondamentale importanza in astrofisica dal momento che esso coinvolge processi che liberano ingenti quantit√† di energia. Infatti, esso interviene nelle emissioni energetiche rilasciate dagli AGN(nuclei galattici attivi) e da alcuni sistemi binari dove oggetti compatti come stelle di neutroni o nane bianche accrescono materia da una stella compagna. Ci√≤ viene spiegato nella Introduzione, dove si confronta l'efficienza radiativa dell'accrescimento con quella della reazione nucleare protone-protone tipica delle stelle in sequenza principale. Nel Capitolo 2 si presentano i modelli matematici descriventi l'accrescimento, primo tra tutti il modello di Bondi classico che tratta l'accrescimento di un buco nero (che pu√≤ essere generalizzato ad un oggetto compatto qualsiasi), immerso in una distribuzione di gas infinita. Esso non tiene conto di eventuali momenti angolari, campi magnetici o effetti relativistici, quindi √® un modello semplicemente idrodinamico. Nonostante trascuri molti aspetti, tale modello √® una base solida per la generalizzazione a casi pi√Ļ complessi, come ad esempio l'accrescimento con electron scattering che apre alla definizione di luminosit√† di Eddington. L'elaborato si conclude con il Capitolo 3 nel quale vengono trattati i sistemi binari. Ci√≤ ci permetter√† di mettere in luce il ruolo chiave della viscosit√† e del campo magnetico nella dinamica dell'accrescimento e che tuttavia sono trascurati nella modelizzazione matematica di Bondi

    The DUNE Far Detector Vertical Drift Technology, Technical Design Report

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    International audienceDUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

    DUNE Offline Computing Conceptual Design Report

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    This document describes Offline Software and Computing for the Deep Underground Neutrino Experiment (DUNE) experiment, in particular, the conceptual design of the offline computing needed to accomplish its physics goals. Our emphasis in this document is the development of the computing infrastructure needed to acquire, catalog, reconstruct, simulate and analyze the data from the DUNE experiment and its prototypes. In this effort, we concentrate on developing the tools and systems thatfacilitate the development and deployment of advanced algorithms. Rather than prescribing particular algorithms, our goal is to provide resources that are flexible and accessible enough to support creative software solutions as HEP computing evolves and to provide computing that achieves the physics goals of the DUNE experiment

    Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora

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    International audienceThe Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/cc charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1¬Ī0.6\pm0.6% and 84.1¬Ī0.6\pm0.6%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation