Figure 1
(a) The geometry of large-angle convergent-beam electron diffraction (LACBED) for one diffracted beam, ignoring all other diffracted beams. The Bragg condition is satisfied when the incident and exit beams make an angle [\theta_{hkl}] to the diffracted planes, defining a cone. This gives a parabola on the diffraction pattern which, because of the very small Bragg angle, appears as a straight line in an LACBED pattern (b), taken from a [100] silicon crystal. (c) The corresponding CBED pattern, with a small part of the LACBED pattern visible in the [2{\overline 2}0] disc.  [article HTML]