In situ monitoring the optical properties of dielectric materials during ion irradiation

In this work we have used in situ reflectance to study structural modifications in silica and quartz irradiated with swift heavy ions. Quantitative analysis of reflectance spectra allowed us to (i) obtain the detailed kinetics of surface modification and (ii) reconstruct the refractive index profiles created in the irradiated materials. We have shown that in situ reflectance yields very accurate results; for instance, track radii and irradiation threshold in silica and quartz obtained from our measurements are similar to those reported in the literature. In particular, reflectance has several advantages over Rutherford Backscattering in the channeling configuration (RBS-C) because it can be measured in situ (allowing recording of detailed kinetics not attainable by RBS-C), requires less sophisticated equipment and, more importantly, can be used with any material whereas RBS-C is restricted to mono-crystalline materials.