Résumé
Around the late 1970s, research and case studies began to emerge linking the use of high-silica glasses to nuclear waste management. The work of Simmons[1] in 1979 has demonstrated that the fixation of radioactive wastes is feasible in high-silica glasses of good chemical durability. With the discovery of numerous extraction agents, the concept of ”separation / conditioning process” was brought up as the optimization of the Simmons process in which all porous materials can be used. Furthermore, since the discovery of ordered mesoporous silica material, more recent attention has focused on its potential application as an alternative process for treating radioactive effluents containing actinides and fission products.Concurrently, studies in the field of irradiation have shown special behavior of mesoporous materials under irradiation. On the one hand, radiation tolerance of mesoporous metallic foam has been reported by Bringa et al.[2]. On the other hand, studies[3] [4] have highlighted the collapse of the porous network of silica-based materials induced by the ballistic or electronic radiation damage. In this way, a precise knowledge of the damage induced due to the radiation in those materials is then required. In this work, thin films (v60 nm) of mesoporous silica deposited by dip-coating onto silicon wafers were irradiated at IRRSUD (GANIL) with ions having a stopping power between 1 keV/nm to 12 keV/nm. These samples were analyzed before and after irradiation by X-ray reflectometry (XRR) and scanning / transmission electron microscopy (SEM, TEM, STEM) to investigate the evolution of the porous structure and also by spectroscopy (nuclear magnetic resonance, Fourier-transform infrared spectroscopy) to evaluate the modification of the silica network. Possible mechanisms have been proposed and discussed in order to explain and describe the evolution of the mesoporous structure under irradiation.