Development of a triple beam irradiation facility

A triple beam ion irradiation facility has been developed to study the syne rgistic effects of displacement damage, helium and hydrogen atoms on micros tructural changes of materials under irradiation environments simulating a fusion reactor. The system consists of a vacuum chamber and three beamlines , which are connected with each electrostatic accelerator. Samples can be i rradiated in the wide temperature range from liquid nitrogen to 1273 K in t he chamber by replacing two kinds of sample stages alternatively. An austen itic stainless steel was simultaneously irradiated with triple beam of nick el, helium and hydrogen ions at 573-673 K using this facility and TEM obser vations were carried out from a cross sectional view normal to the incident surface. It was shown that the number density of dislocation loops decreas ed in the region where hydrogen and helium were deposited in comparison wit h ones in the region where only displacement damage was induced to a simila r damage level. (C) 1998 Elsevier Science B.V. All rights reserved.