Deuterium retention in MeV self-implanted tungsten: Influence of damaging dose rate

Recrystallized, polycrystalline tungsten was self-damaged by 20 MeV tungsten ions up to a calculated damage dose in the damage peak of 0.23 dpa. The time to acquire this dose and hence the average damaging dose rate was varied from 6 x 10(-3) to 4 x 10(-6) dpa/s, the latter coming close to the damage dose rate expected from fusion neutrons in future devices such as ITER and DEMO. One series was conducted at 295 K and one at 800 K to check for possible effects of defect evolution at elevated temperature. The created damage was decorated afterwards with a deuterium plasma at low ion energy of < 15 eV and low flux of 6 x 10(19) D/m(2) until saturation to derive a measure for the defect density that can retain hydrogen isotopes. 3 He nuclear reaction analysis (NRA) was applied to derive the deuterium depth profile and the maximum concentration in the damage peak. Neither for the 295 K nor for the 800 K series a variation in deuterium retention with damage dose rate was found. (C) 2017 The Author. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.