Abstract
The black-white (B-W) stereo technique has been critically assessed and applied to the determination of the nature of small point-defect clusters in copper produced by Kr+ heavy-ion irradiation at room temperature. Several precautions were introduced in an attempt to improve the reliability of the analysis. It was found that most defects lying in the first approximately 10 nm of the foil are vacancy in nature, together with some of the deeper clusters. There was no unequivocal evidence for interstitial clusters. Some were more likely to be interstitial than vacancy on the criteria chosen, although the evidence is weak. Defects sometimes showed inconsistent contrast from one imaging condition to another, demonstrating the difficulty of placing them in the layer structure with complete confidence. The near impossibility of establishing that interstitial clusters are not present is shown by the fact that over half (53%) the total number of clusters could not be analysed because they did not show clear B-W contrast in a minimum number of imaging conditions. Various correlations are made between parameters such as defect sizes with the depths of the defects in the foil.
