Deuterium retention in tungsten

grantor: University of TorontoFor deuterium implantation of pure W foil at 300 K, the amount of D trapped in the material approaches a saturation level of ${\sim}6\times 10\sp{20}$ D/m$\sp2$ for incident fluence ${\ge}10\sp{23}$ D/m$\sp2,$ independent of ion energy or specimen history. For temperatures between 350 and 550 K, higher retention levels are observed, but these levels depend on ion energy, fluence and implantation history. Fluence dependence measurements at 500 K show no sign of saturation below $3 \times 10\sp{24}$ D/m$\sp2$ and the amount retained appears to be diffusion limited. Experiments with pure W foil related to the effect of ion-induced damage on deuterium retention showed that ion-induced surface modifications could affect D-retention. The D retention characteristics of a W-1% La$\sb2$O$\sb3$ tungsten alloy are similar to that of pure W foils, except the amount retained tends to saturate at fluences $>$10$\sp{24}$ D/m$\sp2$ (500 eV/D$\sp+$) and 500 K.M.A.Sc