Influence de la température sur la pénétration des électrons dans les cristaux d'or observés en microscopie électronique sous 100 et 1000 kV

Abstract

Influence OF TEMPERATURE ON ELECTRON PENETRATION IN GOLD CRYSTALS OBSERVED IN ELECTRON MICROSCOPY AT 100 AND 1000 kV Observation of crystals in electron microscopy is limited mainly by electron absorption in the specimen. Of the different processes, the contribution from thermal diffusion scattering by the atoms is important especially for heavy materials such as gold. In order to appreciate these effects, we have studied the modifications of image intensity profiles when the temperature decreases. We have used gold crystals at temperatures between 300 and 10 K. Contrast modifications due to reduction of temperature depend on the accelerating voltage as shown by the results obtained at 100 kV and at 1000 kV, interaction effects being much more important for the latter. Comparison between theoretical and experimental intensity curves tests the validity of models proposed by different authors for determining the complex potentials of the crystal lattice.