CALCULATION OF THE INFLUENCE OF INELASTIC SCATTERING OF ELECTRONS ON ELECTRON MICROSCOPE IMAGES OF SINGLE CRYSTALS Taking inelastic scattering by plasmons into consideration in the calculation of the intensity distribution in images of single crystals, common experimental observations in electron microscopy are accounted for.

Calcul de l'influence de la diffusion inélastique des électrons sur les images de monocristaux

Surface Plasma Oscillations and Related Surface Effects in Solids

A general procedure has been devised for the analysis and prediction of electron energy-loss spectra which may be described in terms of two basic inelastic scattering processes, one being more probable than the other. The procedure is illustrated by its application to the analysis of the characteristic energy-loss spectra of evaporated Al films as seen by electron transmission. The procedure accounts for plural surface-volume and volume-volume scattering and the modifying effect of the finite resolution of the energy analyser. Good agreement is found between observed and calculated spectra (23-70 kev energy electrons) for energy losses less than about 70 ev. The method allows the determination of the important energy-loss distribution corresponding to a single-volume loss and provides a basis for estimating the importance of energy-loss processes not specifically accounted for in the fitting procedure.

Convolution effects in electron energy-loss spectra recorded by electron transmission

The energy loss spectrum of electrons and the loss function

Energy spectra of 50 kev-electrons scattered inelastically in thin Al foils of various thicknesses have been measured as a function of scattering angle. The measured angular distribution of electrons which have excited one or more volume plasmons is compared with theoretical calculations and good agreement is obtained. From the integrated intensities, the mean free path of 50 kev-electrons for plasmon excitation is determined with an accuracy of about 20%. The resulting value Λ=820 A is in good agreement with the theoretical value calculated fromFerrell's free electron model (Λ=760A).

P. Wienhold

Papers

Differentieller und totaler Wirkungsquerschnitt für die Anregung des 15 eV-Al-Plasmaverlustes durch Elektronen