Going towards the dual energy x-ray radiographic system for material recognition purposes

Non Destructive Testing (NDT) has become the mostused technique to inspect objects in order to find manufacturingdefects (quality control), investigate contents (customcontrol), detect damages (structural control).However, the mono-energetic NDT can only discover adensity variation in the analyzed sample, but in most casesno hypothesis can be done on its composition; a completeinspection of an object would require the recognition of thematerials composing the analyzed sample, and this can beachieved by means of the dual energy x-ray radiography.In this context, the INFN - Gruppo Collegato di Messinais planning to implement the radio-tomographic system ofthe Dipartimento di Fisica, Universit`a di Messina, based ona 5 MeV electron linac, to the aim to provide dual energyx-ray beams for material recognition purposes.Preliminary caculations have been performed to evaluatethe different electron energies obtainable acting on the linacparameters. Moreover, according to a theoretical study onthe x-ray transmission for two chosen x-ray energy spectra,the material recognition should be possible by means of thedeveloped radio-tomographic device.