Irradiation has been performed, at 1.5 kGy dose, by means of
5 MeV electron accelerator of the Physics Department of
University of Messina (Auditore et al., 2004). This accelerator is
a research tool, designed in collaboration with the ENEA Accelerators
Group (Frascati, Rome); it has auto focusing accelerating
structure, able to deliver an extremely collimated electron beam
with 4 mm2 surface spot.