Thermal Desorption of Deuterium from Be, and Be with Helium Bubbles

摘要

Deuterium desorption measurements carried out on a single=-crystalline beryllium sample are presented. Deuterium ions were implanted at room temperature at the energy of 0.7 and 1.2 keV up to doses ranging from 10~19 to 3.6x10~21 m~-2. In order to eliminate the influence of the beryllium-oxide surface layer, before the implantation the surface of the sample was cleaned by argon sputtering. After the implantation the sample was annealed up to 1200 K at a constant rate of 10 K/s. Deuterium released from the sample was monitored by a calibrated quadrupole mass-spectrometer. The desorption spectra revealed two differnet contributions. One is a well defined and very narrow peak centered around 450 K. This peak is observed only at high implantation doses > 7.8x10~20 m~-2, which is close to the deuterium saturation limit of 0.3 D/Be and is related to deuterium release from blisters or interconnected bubbles. The activation energy of 1.1 eV and the threshold implantation dose are consistent with the values reported in literature.