Variation of Electron Microscopic Thickness Fringes of Aluminium Single Crystals with Energy Loss

From the observation of energy-filtered thickness fringes in electron microscopic bright-field and dark-field images of thin aluminium single crystal films it is found that (1) the fringe positions and distances are almost the same regardless of the filter potential, and (2) the fringe intensities of no-loss, 7 and 15 eV loss electrons decrease slowly as the thickness increases but those of 3 and 10 eV loss electrons decrease rapidly. These effects are explained by using a n -slice dynamical theory in which the effect of energy losses is taken into account.