(Contact person V. Ioannou-Sougleridis)

This research activity is implemented by the Eurofusion consortium. Initially it was conducted within the frame of the program WPJET3 (“Technological exploitation of Deuterium-Tritium operation”) and now has extended into the WP “Preparation for ITER operations”. The activity is carried out in collaboration with the INRaSTES of NCSR “Demokritos”. The main task is to determine the radiation induced damage of high-quality dielectric materials with a particular optical (i.e., optical window) or insulating functionality, when exposed to high fluence of neutrons (14 MeV) and γ-rays within the Joint European Torus (JET) tokamak fusion reactor. The samples that will be examined in 2022 were exposed to the record breaking 59 MJ of sustainable fusion energy that was achieved at JET during the DTE2 (second experiment of deuterium-tritium) campaign. Among the selected materials for irradiation are sapphire and polycrystalline aluminas and aluminum nitrides. The implementation of this activity required the introduction of new to the group techniques such as the diffuse reflectance spectroscopy (DRS), the photoluminescence spectroscopy, the Dielectric spectroscopy of high resistivity materials within the frequency range 0.01Hz to 1 MHz, and the method of thermally stimulated currents (TSC).