DETERMINATION OF NATURE OF DEFECT CLUSTERS IN IRRADIATED METALS BY RUTHERFORD BACKSCATTERING

The capability of the Rutherford backscattering (RBS) technique to determine the nature of defect clusters in implanted metals has been examined. In order to avoid impurity-defect interaction effects, self-ion irradiation at 200 keV (dose: 1 × 1016 Cu+ ions/cm2) in a 〈110〉 copper single crystal was chosen for this study. Axial channeling along a 〈110〉 direction was performed with a helium ion beam at energies of 2 000, 2 900, and 3 500 MeV. All aligned spectra show prominent 'knees' at similar depths. The analysis of backscattering spectra shows that the observed dechanneling cross-section follows an E- 1 2 dependence on the energy E of the analysing beam. According to Quéré's analysis, such an energy dependence indicates that the dechanneling centres are interstitial atoms. This result is in partial agreement with the earlier TEM studies which showed the presence of interstitial dislocation loops in self-ion-irradiated copper at high doses. © 1978.