Design and Performance of Fast, a Tracker for Antiproton Physics

The antiproton annihilation cross section on different nuclei was measured by the OBELIX collaboration at LEAR (CERN) during the '80s and '90s; its dependence on the atomic mass number A, in the momenta range 200-800 MeV/c, was found to be A^2/3. Low statistics measurements at lower energies (60 MeV/c) showed some anomalies that suggested the need for new experiments to investigate about them and to increase statistics. For these reasons, a new pbar cross section experiment has been proposed at the end of 2004, and a scintillating fiber tracker (FAST, Fiber Antiproton Scintillating Tracker) has been built to perform a direct annihilation cross section measurement at the Antiproton Decelerator (AD) at CERN. This thesis work decribes the design and the development of the detector, its assembly and commissioning phase results. The tests with a prototype and the comparisons with a Montecarlo simulation are reported too. In the last part, the data taking setups of September 2006 and July 2007 are presented.