Clarification of the properties and accumulation effects of ion tracks in CeO2

In order to understand the properties of ion tracks and the microstructural evolution under accumulation of ion tracks and Xe ions in CeO2, 70–210 MeV Xe10∼14+ ions irradiation examinations and pre-implantations of 240 keV Xe ions have been done at a tandem accelerator facility and an ion implanter facility of JAEA-Tokai. The microstructure observations were performed by means of a transmission electron microscope (TEM) and a scanning electron microscope (SEM) in CRIEPI. Measurements of the diameter of ion tracks with the irradiation temperature, between room temperature and 800 °C, clarify that the prominent changes of ion tracks are hardly observed up to 800 °C. By cross-sectional observation, it becomes clear that the threshold electronic stopping power of ion track formation is around 15–16 keV/nm in case of Xe ions irradiation. 210 MeV Xe14+ ion irradiations cause a surface roughness on CeO2 in the ion fluence range between 5 × 1014 ions/cm2 and 1 × 1015 ions/cm2.