In-Situ Observation of Radiation Damage Using a Combined Facility of Electron Microscope and Heavy-Ion Accelerator(s) -History and Future Prospectives-

Radiation effects in materials for fission and fusion reactors are caused by fast neutrons which produce cascade damage, which has been known to be considerably different from simple Frenkel pairs produced by relativistic electrons. In-situ observation of radiation damage using a combined facility of electron microscope and heavy-ion accelerators has been a powerful tool to investigate the nature of the cascade damage. In this overview, brief historical survey of this experimental technique will be given, followed by the results and discussions on cascade damage mainly in gold will be reviewed. Careful considerations will be required to generalize the results to other metals as well as to other experimental conditions. Finally, there are a number of points to be developed for better understanding of cascade damage and for extending the "in-situ" techniques to other materials as non-metallic solids and to other intriguing phenomena.