Retention and release of deuterium implanted in W and Mo

Retention and thermal release of deuterium implanted in W with various carbon contents were studied by ion beam analysis techniques. The correlation between implantation induced defects and deuterium trapping in W was examined in comparison with that in Mo. The D concentration in the near surface layer of the W crystal was higher than that in the Mo crystal during 10 keV D ₂⁺ implantation at room temperature. In case of the D implanted Mo crystal, the isolated interstitial atoms were mainly recognized by the ion channeling. On the other hand, a large lattice distortion caused by the extended defects was observed in the near surface layer of the D implanted W at room temperature, and the distortion was not effectively formed above 390 K. The appreciable amount of the retained D atoms was released from pure W at around 450 K at which the lattice distortion was partly annealed out. The thermal release of D retained in the carbon containing W abruptly occurred at about 350 K, independent of the carbon contents.