The Muon Portal Project: construction and preliminary tests of the detection modules

In the last years, the demand for increasing the control security at borders and ports has lead to the development of innovative and reliable techniques to inspect the contents of traveling containers. Traditional systems based on X-ray inspection cannot be employed on occupied vehicles, since the energy or dose required would be too high in order to penetrate big cargos.One of the most promising technique is the so-called muon tomography: by measuring the deflection suffered by cosmic muons when traversing high-Z materials, it is possible to reconstruct a 3D image of the volume to be inspected and detect the presence of fissile (U, Pu) samples in a reasonable amount of time (a few minutes). The Muon Portal is a recently started Project aiming at the construction of a large area tracking detector that exploits the muon tomography technique to inspect the contents of traveling cargo containers. The detection setup is based on eight position-sensitive planes (giving X- and Y-coordinates). Each detection planes are segmented into strips of extruded plastic scintillators with wavelength-shifting (WLS) fibres to transport the light produced in the scintillator material to the photo-sensors at one of the fibre ends. In this Thesis the relevance of the muon tomography technique, the design of the Muon Portal Project, the characterization of scintillator strips, WLS fibers and SiPM devices for the detection modules are discussed. Some preliminary results on the tests of the first detection modules, the current installation status and a possible use of the Muon Portal detector in cosmic ray physics are also presented.