Hillock formation at surface of ceramics irradiated with swift heavy ions

Ishikawa, Norito   ; Taguchi, Tomitsugu*

In this study, CeO, a surrogate for nuclear fuel ceramics, was irradiated with 200 MeV Au ions at oblique incidence. Observation of as-irradiated samples by transmission electron microscope (TEM) shows that hillocks are created not only at the wide surfaces, but also at the side edge of the thin samples. Since the hillocks created at the side edge can be imaged without overlapping of matrix image, their shape and crystallographic features can be revealed. The present method is also applied for observing hillocks created for CaF, which has the same crystal structure with CeO. Although hillock-like shape has been reported so far for hillocks of CaF, the present study revealed that not only hillock-like shaped but also polyhedron shaped hillocks are created by irradiation with swift heavy ions. The polyhedron shaped hillocks have faceted surfaces reflecting the crystal lattice structure.