A NMR and SANS study of alkali-borosilicate behaviour under thermal neutron irradiation

The internal structure of several alkali-borosilicate glasses has been studied when exposed to a high thermal neutron flux. More specifically, the different glasses we are interested in are widely used around the globe for neutron guide manufacturing and show drastically different resistance to irradiation. Samples were irradiated with the thermal flux from T4 experimental tube in ILL¿s High Flux Reactor up to a fluence of several n/cm. The experimental tools employed for the structural analysis were Nuclear Magnetic Resonance (NMR) and Small Angle Neutron Scattering (SANS). NMR measurements allowed to detect the modification of atoms¿ close environment and these results have been correlated to evolutions at macroscopic scale. In addition, neutron scattering measurements have demonstrated the possibility to detect phase segregation in a zinc-alkali-borosilicate.