The implantation and retention of D ions at room temperature was studied in pure and C-implanted single crystals. Pre-implantation was performed using 40keV C ions, and implantation was performed using 10keV D ions. The latter range was confined to the C-modified layer. Upon using 100keV D ions, the range extended beyond the C-modified layer. The range distributions were investigated in situ by using 1MeV 3He ions and by analyzing the energy distributions of α-particles arising from the D(5He,p)α reaction. The amount of retained D was deduced from the p-integral. The range distribution of C was deduced from the back-scattered 3He energy distribution. It was found that C pre-implantation influenced D retention only if the range of the D ions was confined to the C-modified surface layer. In this case, diffusion of D beyond the ion range distribution did not occur and the amount of retained D was smaller than that in pure crystals. At D energies which overshot the C-modified layer, retention occurred in a dislocation zone of up to 1μm and the total amount retained was the same as that for C-implanted and pure samples.

Retention of Ion-Implanted Deuterium in Tungsten Pre-Irradiated with Carbon Ions. V.K.Alimov, K.Ertl, J.Roth, K.Schmid: Journal of Nuclear Materials, 2000, 282[2-3], 125-30