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One of the problems in the analysis of nucleus-nucleus collisions is to get information on the value of the impact parameter b. This work consists in the application of pattern recognition techniques aimed at associating values of b to groups of events. To this end, a support vec- tor machine (SVM) classifier is adopted to analyze multifragmentation reactions. This method allows to backtracing the values of b through a particular multidimensional analysis. The SVM classification con- sists of two main phase. In the first one, known as training phase, the classifier learns to discriminate the events that are generated by two different model:Classical Molecular Dynamics (CMD) and Heavy- Ion Phase-Space Exploration (HIPSE) for the reaction: 58Ni +48 Ca at 25 AMeV. To check the classification of events in the second one, known as test phase, what has been learned is tested on new events generated by the same models. These new results have been com- pared to the ones obtained through others techniques of backtracing the impact parameter. Our tests show that, following this approach, the central collisions and peripheral collisions, for the CMD events, are always better classified with respect to the classification by the others techniques of backtracing. We have finally performed the SVM classification on the experimental data measured by NUCL-EX col- laboration with CHIMERA apparatus for the previous reaction.

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The Time-Of-Flight (TOF) detector of ALICE is designed to identify charged particles produced in Pb--Pb collisions at the LHC to address the physics of strongly-interacting matter and the Quark-Gluon Plasma (QGP). The detector is based on the Multigap Resistive Plate Chamber (MRPC) technology which guarantees the excellent performance required for a large time-of-flight array. The construction and installation of the apparatus in the experimental site have been completed and the detector is presently fully operative. All the steps which led to the construction of the TOF detector were strictly followed by a set of quality assurance procedures to enable high and uniform performance and eventually the detector has been commissioned with cosmic rays. This work aims at giving a detailed overview of the ALICE TOF detector, also focusing on the tests performed during the construction phase. The first data-taking experience and the first results obtained with cosmic rays during the commissioning phase are presented as well and allow to confirm the readiness state of the TOF detector for LHC collisions. / Il rivelatore Time-Of-Flight (TOF) di ALICE (A Large Ion Collider Experiment) è progettato per l'identificazione delle particelle cariche prodotte nelle collisioni nucleari di LHC (Large Hadron Collider) allo scopo di studiare la fisica della materia fortemente interagente ed il Quark-Gluon Plasma (QGP). Il rivelatore sfrutta la tecnologia innovativa MRPC (Multigap Resistive Plate Chamber) che garantisce le eccellenti prestazioni richieste ad un vasto sistema per la misura del tempo di volo. La costruzione e l'installazione dell'apparato nel sito sperimentale sono state completate ed il rivelatore è attualmente operativo in tutte le sue parti. Tutti i passi necessari per la costruzione del rivelatore finale sono stati accompagnati da una serie di procedure per il controllo della qualità della produzione allo scopo di garantire prestazioni elevate ed uniformi; infine il corretto funzionamento del rivelatore è stato verificato con raggi cosmici. Questo resoconto ha lo scopo di fornire una visione d'insieme dettagliata del rivelatore TOF di ALICE, focalizzando l'attenzione anche sui test effettuati durante le fasi di costruzione. Oltre ad una breve descrizione dell'esperienza acquisita nelle prime fasi di presa dati sono presentati i primi risultati ottenuti con raggi cosmici che confermano promettenti prestazioni del rivelatore TOF per lo studio delle collisioni di LHC.

The fundamental goal of this thesis is the determination of the isospin dependence of the Ar+Ni fusion-evaporation cross section. Three Ar isotope beams, with energies of about 13AMeV, have been accelerated and impinged onto isotopically enriched Ni targets, in order to produce Pd nuclei, with mass number varying from 92 to 104. The measurements have been performed by the high performance 4pi detector INDRA, coupled with the magnetic spectrometer VAMOS. Even if the results are very preliminary, the obtained fusion-evaporation cross sections behaviour gives a hint at the possible isospin dependence of the fusion-evaporation cross sections.