Journal of Electron Microscopy 48(5): 489-493 (1999)
© 1999 Oxford University Press
Particularities of high-voltage electron microscopy: instrument design, defect imaging and in situ investigation in ‘thick’ specimens
1DMSC, ONERA 29 Av. de la Division Leclerc, F-92322 Châtillon Cedex, France
2LMSSM, ECP, Grande Voie des Vignes F-92295 Châtenay-Malabry Cedex, France
The present paper gives a critical analysis and a reflection on the particularities of HVEM, illustrated by practical examples. The instrument, i.e. the attachments and the microscope itself, will be considered first. In this context the physical approach, which has led to the development of efficient equipment, will be emphasized. As regards the microscope itself, the specific design of the 1.2 MV GESPA microscope, which has not only permitted successful in situ experiments in ‘thick’ specimens, but has also attained a very good resolution in an adapted version, will be considered. The dual aspect of defect imaging will also be discussed, i.e. a positive aspect in which good quality images of defects in ‘thick’ specimens may be obtained under given conditions and a negative aspect, which is emphasized in high temperature observations of defects in ordered phase superalloys. Finally, the fact that in situ experiments on ‘thick’ specimens should not be considered independently but as a part of a broader investigation involving many other mesoscopic, macroscopic or nanoscopic techniques will be emphasized and illustrated by examples.
Keywords HVEM, instrumentation, contrast, electron channelling, in situ experiments
Received 18 November 1998, accepted 23 June 1999