Collimazione di fasci di adroni con cristalli piegati in UA9

UA9 is an experiment that study the feasibility of a new collimation system for charged particles beam. It's a two stage system, in which the first is composed by a bent crystal and the second by a massive absorber. The experiment is performed on the SPS ring at CERN. In this thesis of Laurea Specialistica in Fisica Nucleare and Subnucleare, are reported the results of the last year of measurements. In particular the structure of this thesis is divided in four big chapters. We'll start with a first part in which is reported the interaction theory between charged particles and bent crystals. In the second part are described the accelerators run settings useful for illustrate the collimation method for the halo around the beam, and the advantages to substitute the primary amorphous stage with a bent crystal. On the third section is reported the experimental layout description, included an illustration of the accelerator parameters during the collimation tests with bent crystal. Here are also reported the various procedures of measurements used, with the relative observables definitions. We'll end with the fourth section in which are exposed the main results obtained during the collimation tests with protons or lead ions inside the machine, and the relative analysis with which they are derived.