Characterization of proton irradiation-induced defect in the A508-3 steel by slow positron beam

Proton irradiated A508-3 steel samples at room temperature were characterized by slow positron Doppler broadening spectroscopy to investigate the evolution of the irradiation-induced defects. S parameters of the irradiated samples were higher than those of the unirradiated samples. The S-W plot indicated that only one type of defect was presented in all the samples. These defects seem to be the vacancy-impurity complexes (associated with C, H, Mn or Ni) or divacancies. On the basis of the assumption that irradiation induced-defects consist of mono-vacancies, the concentration of these defects (similar to 10(20)/cm(3)) rapidly increases at the low dose (below about 0.15 dpa) and then tends to saturate at high dose (up to 0.35 dpa). (C) 2012 Elsevier B.V. All rights reserved.