Deuterium retention in beryllium, molybdenum and tungsten at high fluences

The retention of 1 keV D in room-temperature beryllium, molybdenum and tungsten has been measured as a function of fluence, for incident D-3(+) fluences ranging from 10(21) to 10(25) D/m(2). The amount of D retained in Be tend to saturation (similar to 2.7 x 10(21) D/m(2)) for incident fluences > 10(22) D/m(2), with an estimated saturation concentration (based on TRIM vectorized for multicomponent targets, TRVMC, range calculations) of similar to 0.39 D/Be within the implantation zone, this retention level is similar to what has been observed for single-crystal graphite, viz, similar to 2.2 x 10(21) D/m(2) or similar to 0.4 D/C. For fluences greater than about 10(22) D/m(2), the amount of D retained in tungsten also tends to saturation at similar to 6 x 10(20) D/m(2). Assuming a maximum ion implantation depth of similar to 40 nm (as calculated by TRVMC), this amounts to a concentration of similar to 0.24 D/W. The amount of D retained in Mo does not appear to reach saturation over the fluence range studied. D retention in Mo is lower than that in W for incident D fluences less than or similar to 10(25) D/m(2), at which point the two retention curves cross.