BSTRACTAlthough accelerator-based ion irradiation has been widely accepted to simulate neutron damage

neutron-atypical features need to be carefully investigated. In this study

we have shown that Coulomb force drag by ion beams can introduce significant amounts of carbon

nitrogen

and oxygen into target materials even under ultra-high vacuum conditions. The resulting compositional and microstructural changes dramatically suppress void swelling. By applying a beam-filtering technique

introduction of vacuum contaminants is greatly minimized and the true swelling resistance of the alloys is revealed and matches neutron behavior closely. These findings are a significant step toward developing standardized procedures for emulating neutron damage.