Positron annihilation studies on the nature and thermal behaviour of irradiation induced defects in tungsten

Abstract

Abstract Positron Annihilation Lifetime Spectroscopy has been performed with a pulsed positron beam to investigate the nature and evolution of implantation‐induced defects created in the track region (TR) of 800 keV 3 He ions at different fluences. At high fluence ‐ 5×10 16 cm –2 ‐ lifetime decomposition exhibits a predominant (98%) positron lifetime of 200 ps which is attributed to irradiation induced monovacancy. The increasing average lifetime as a function of the post‐implantation annealing temperature has allowed to identify vacancy clustering due to vacancy migration (that occurs from 473 K). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)