Observation of dependent to independent Bloch wave transition in Kikuchi patterns

The transition from dependent to independent Bloch waves in high-energy electron diffraction theory is demonstrated by observing the disappearance of subsidiary fringes in Kikuchi patterns as the crystal thickness is increased. Comparison is made between experimental and computed Kikuchi band profiles in Si. It is shown that the subsidiary fringes provide a method for thickness determination in zone axis convergent-beam electron diffraction patterns from relatively thin crystals. (orig.)