Deuterium retention in tungsten simultaneously damaged by high energy W ions and loaded by D atoms

Abstract

Deuterium retention was for the first time measured in tungsten samples simultaneously irradiated by W ions and exposed to D atoms at five different temperatures from 450K to 1000K. In order to obtain information on the defect concentration, samples were afterwards exposed to D atoms at 600K to populate the created defects. The results were compared to different sequential damaging/exposure experiments. Synergistic effects were observed, namely, higher D concentrations were found in the case of simultaneous damaging and D-atom loading as compared to sequential damaging at elevated temperatures and populating the defects afterwards. However, the deuterium retention is still lower as compared to sequential damaging at room temperature and post-damaging annealing. The observations are explained by stabilization of defects by the presence of solute hydrogen in the bulk that would annihilate at high temperatures without the presence of hydrogen. Results of simultaneous W-ion damaging and D exposure at elevated temperatures were also compared to a sequential experiment of W-ion damaging at room temperature and then D-atom loading at high temperatures showing that thermal D de-trapping dominates deuterium retention at high temperatures. Keywords: Tungsten, Deuterium retention, Displacement damage, Neutral atoms, NRA