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Journal of Electron Microscopy 48(4): 323-332 (1999)
© 1999 Oxford University Press
On the application of the weak-beam technique to the determination of the sizes of small point-defect clusters in ion-irradiated copper
1Department of Materials, University of Oxford Parks Road, Oxford 0X1 3PH, UK
2Materials Science Division, Argonne National Laboratory IL 60439, USA
3Faculty of Engineering, Hiroshima University Higashi-Hiroshima 739-8527, Japan
*To whom correspondence should be addressed. E-mail: mike.jenkins{at}materials.oxford.ac.uk
We have made an analysis of the conditions necessary for the successful use of the weak-beam technique for identifying and characterizing small point-defect clusters in ion-irradiated copper. The visibility of small defects was found to depend only weakly on the beam convergence. In general, the image sizes of small clusters were found to be most sensitive to the magnitude of sg, with the image sizes of some individual defects changing by large amounts with changes in sg as small as 0.025 nm–1. The most reliable information on the true defect size is likely to be obtained by taking a series of 5–9 micrographs with a systematic variation of deviation parameter from 0.2–0.3 nm–1. This procedure allows size information to be obtained down to a resolution limit of about 0.5 nm for defects situated throughout a foil thickness of 60 nm. The technique has been applied to the determination of changes in the sizes of small defects produced by a low-temperature in-situ irradiation and annealing experiment.
Keywords weak-beam microscopy, defects, clusters, irradiation damage
Received 16 October 1998, accepted 23 March 1999