Deuterium accumulation in beryllium in contact with atomic deuterium at 740 K

The interaction of deuterium atoms with type TIP-30 beryllium has been studied. A plasma source with a heated cathode was used to produce deuterium atoms. The sample was under positive potential of +80 V to repulse the deuterium ions. The atomic flux was estimated at 1016 cm-2 s-1. After exposures to different doses at 740 K, the deuterium distribution and inventory in the samples were measured by means of elastic recoil detection (ERD) and thermal desorption spectroscopy (TDS) methods. The experiments showed that when in contact with atomic deuterium, beryllium absorbs deuterium up to concentrations of (6-8) x 1021 D/cm3. Deuterium penetrates deeply into the beryllium bulk. The penetration depth depends on the exposure time and reaches 400 nm after 240 min exposure. The main features of deuterium accumulation in beryllium during the atom exposure are very similar to those during the deuterium ion implantation, and this points out the similarity of the mechanisms of deuterium spread into beryllium, perhaps through the formation of the bubbles. (orig.)