Helium induced damage is one of the major contributing factors leading to projected loss of integrity of the first wall in fusion reactor systems. Previous electron microscopy investigations of the surface and bulk damage induced by energetic He+ bombardment of vanadium revealed that only a small fraction of the total implanted helium could be accounted for after irradiation. This fraction was contained in observable bubbles with diameters, d > 4 nm. In this study transmission electron microscopy techniques were used to establish the development of a new population of small diameter bubbles (d < 4 nm) after post-irradiation annealing treatments. A characteristic bimodal distribution function for the bubble population was found after annealing. This distribution has a strong peak at small diameters induced by growth of helium-vacancy clusters from the available thermally created vacancies.
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Materials Science(all)