Variation of Electron Diffraction Intensity with Wavelength of Electrons

Intensity of electron diffraction Debye-Scherrer rings of evaporated films of aluminum, nickel, gold and sodium fluoride was measured for electrons in a range of wavelength λ from 0.1 to 0.025 Å (accelerating voltage from 15 to 200 kV). Logarithm of observed intensity varies linearly with λ 2 for not too large λ in accordance with the dynamical theory of two-wave approximation. The value extrapolated to λ=0 coincides with the kinematical value within experimental errors 5∼15%. The gradient of the linear relation, too coincides with the value calculated from the theory. No complication was found which requires explicitly the many-wave theory. The deviation from the linearity for large λ was reasonably explained as a result of absorption.