Electron microscopic observations were performed in situ in order to investigate damage evolution in single crystals during H2+ ion bombardment in an electron microscope linked to an ion accelerator. Bombardment was carried out at room temperature, 400C, 650C or 800C, using 15keV H2+ ions, for 1h at a flux of 1018/m2s. It was observed that there were 2 temperature ranges which were characteristic of the formation and growth of defect clusters. In the lower temperature range, below 400C, dislocation loops and bubbles formed uniformly. In the higher temperature range, above 650C, bubbles formed almost at the same time as the dislocation loops and were located preferentially within the planes of the dislocation loops. As bombardment continued, the number of bubbles within the loops increased with loop growth, but the size of the bubbles hardly changed. It was suggested that the formation and growth of bubbles was promoted by defects on loop planes in the high-temperature range.

Radiation Effects on Al2O3 Irradiated with H2+ Ions. S.Furuno, N.Sasajima, K.Hojou, K.Izui, H.Otsu, T.Matsui: Journal of Nuclear Materials, 1998, 258-263, 1817-21