Abstract
Doppler-broadening measurements of the positron annihilation characteristics of both well-annealed and electron irradiated Zr and Ti have been made. Data obtained with the use of both a “hard” (68Ge) and a “soft” (22Na) positron-emitting source were used to yield information about the defect depth distributions of the irradiated materials. Good agreement between these results and theoretical defect profiles, based on electron energy loss calculations, were found for one set of irradiated samples. A striking disagreement between experimental and theoretical defect depth profiles for another set of samples, irradiated under different conditions, was resolved when a hitherto unsuspected H− component of the electron beam was taken into account.