A quantitative study of retention and release of deuterium and tritium during irradiation of γ-LiAlO2 pellets

Abstract

This study reports on the quantification of deuterium in ion-irradiated γ-LiAlO2 pellets as a function of dose and temperature. The γ-LiAlO2 pellets were sequentially irradiated with He+ and D2+ ions to the same fluences of 5 × 1016, 1 × 1017 and 2 × 1017 He+ + D+/cm2 at 188 K. Additional irradiation was performed to 1 × 1017, 2 × 1017 and 4 × 1017 He+ + D+/cm2 at 573 K. A set of the pellets irradiated at 188 K was shipped and stored at low temperatures from 80 to 132 K and characterized using time-of-flight secondary ion mass spectrometry at ~173 K. The deuterium depth profiles show a Gaussian-like distribution in the low-temperature pellets. The total deuterium retention is found to be directly proportional to the ion fluence. About 27 at.% of the implanted deuterium atoms were released from the pellet irradiated to 2 × 1017 He+ + D+/cm2 at 188 K during storage at room temperature for ~1 month. The measured deuterium retention is found to increase initially with ion fluence and tend to saturate at high fluences during ion irradiation at 573 K. The amount of the released deuterium is observed to be quantitatively consistent with that of the released tritium from the standard pellets during neutron irradiation at 573 K.