Accession Number:

ADA029925

Title:

Sem Imaging of Crystal Surfaces using Diffracted Beams,

Descriptive Note:

Corporate Author:

ARIZONA STATE UNIV TEMPE DEPT OF PHYSICS

Report Date:

1976-01-01

Pagination or Media Count:

10.0

Abstract:

Additional information regarding the structure of the surfaces of crystals may be obtained by the use of diffracted beams to form SEM images. Variations of diffracted beam intensities are produced both by surface topography and also by variations in the orientation or composition of the crystal. Image intensities are therefore sensitive indicators of chemical reactions, impurities, crystal imperfections or crystal distortion. A medium energy diffraction-SEM system with an ultra-high vacuum specimen environment has been built and used to demonstrate these possibilities Cowley, et. al., Rev. Sci. Instr 46. 1975, 826-29. This instrument has been applied to the study of the structures of various crystal surfaces. A new surface phase observed to grow on oxidized copper single crystals at about 500 C is attributed to the precipitation of dissolved silver. For a mosaic crystal of pyrolytic graphte diffraction images show clearly the mosaic structure and the presence of crystal defects and allow interpretation of electron channeling effects observed in secondary electron images. Author

Subject Categories:

  • Crystallography
  • Particle Accelerators

Distribution Statement:

APPROVED FOR PUBLIC RELEASE