AbstractThe original experimental results on the study of structural modification of chalcogenide glasses by 60Co γ‐irradiation with energy of 1.25 MeV and dose of 2.41 MGy for As2S3, Ge15.8As21S63.2, Ge9.5As28.6S61.9 and Ge23.5As11.8S64.7alloys using Doppler broadening of annihilation line (DBAL) technique are reported. The γ‐irradiation‐induced effect is analyzed in terms of Doppler S and W annihilation parameters. In particular, the observed different slope of S ‐W plots for glassy (g‐) As2S3 and g‐Ge15.8As21S63.2studied in the unirradiated and γ‐irradiated states indicates that the defect structure of these alloys in the radiation‐modified state is different, obviously, as a result of various mechanisms of radiation‐induced defect formation. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)