Fragmentation measurements with the FIRST experiment

The Phd thesis presented here documents the work performed within the FIRST collaboration. The research work was focused on the analysis of data collected for the interaction of a 12C beam at 400 MeV/nucleon on the thin targets. In particular I have dealt with the calibration of some detectors of the FIRST apparatus, the charge identification algorithm, the tracks reconstruction and the background studies. The results of this analysis work are the differential fragmentation cross sections, here presented, measured as a function of the fragment angle and kinetic energy in the forward angular region (θ . 6◦). Furthermore, I have also studied a possible upgrade of the FIRST experimental apparatus with an improved detector setup to enhance the fragments reconstruction and identification performances. In chapter 1 an introduction to particle therapy will be given and the mechanisms of interaction of ions with matter will be reviewed with a particular focus on the energy range of interest for particle therapy applications. Chapter 2 will deal with the nuclear fragmentation models and measurements. In chapter 3 the FIRST apparatus and the detector calibration strategies will be described. In chapter 4 the analysis techniques used for the reconstruction of fragment tracks in the forward angular region of FIRST and the results of the elemental and isotopic single differental cross sections with respect to angle and energy will be discussed. Finally, in chapter 5, a possible upgrade of the FIRST apparatus will be proposed.