Positron annihilation spectroscopy, based upon positron lifetime measurements and using a pulsed low-energy positron system, was applied to the investigation of defects in irradiated and thermally treated reactor pressure vessel steels. The pulsed low-energy positron system results showed that changes in the microstructures of the steels, as caused by neutron-irradiation and post-irradiation heat treatment, could be sensitively detected. From lifetime measurements for the near-surface (20 to 550nm) region, the defect density in Russian types of reactor pressure vessel steels was calculated by using the diffusion trapping model.

Investigation of Defect Distributions in Neutron-Irradiated and Thermally Treated Reactor Steels by Positron Annihilation. V.Slugen, G.Kögel, P.Sperr, W.Triftshäuser: Applied Surface Science, 2002, 194[1-4], 150-4