Comparative study of radiation-induced damage in magnesium aluminate spinel by means of IL, CL and RBS/C techniques

A comparative study of damage accumulation in magnesium aluminate spinel (MgAl 2 O 4 ) has been conducted using ionoluminescence (IL), cathodoluminescence (CL) and Rutherford Backscattering Spectrometry/channeling (RBS/C) techniques. MgAl 2 O 4 single crystal and polycrystalline samples were irradiated with 320 keV Ar + ions at fluencies ranging from 1 × 10 12 to 2 × 10 16 cm −2 in order to create various levels of radiation damage. RBS/C measurements provided quantitative data about damage concentration in the samples. These values were then compared to the luminescence measurements. The results obtained by IL and RBS/C methods demonstrate a two-step character of damage buildup process. The CL data analysis points to the three-step damage accumulation mechanism involving the first defect transformation at fluencies of about 10 13 cm −2 and second at about 10 15 cm −2 . The rate of changes resulting from the formation of nonluminescent recombination centers is clearly nonlinear and cannot be described in terms of continuous accumulation of point defects. Both, IL and CL techniques, appear as new, complementary tools bringing new possibilities in the damage accumulation studies in single- and polycrystalline materials.