Beschreibung:
<jats:title>Abstract</jats:title><jats:p>From a two beam approximation of the dynamical theory of the relative backscattered electron intensity as a function of direction of incidence, it is shown that the angular width of electron channelling lines on SEM images can be given by the expression: 2 ω<jats:sub><jats:italic>g</jats:italic></jats:sub> = 2/ξ<jats:sub><jats:italic>g</jats:italic></jats:sub>|<jats:bold><jats:italic>g</jats:italic></jats:bold>|, where ξ<jats:sub><jats:italic>g</jats:italic></jats:sub> and <jats:bold><jats:italic>g</jats:italic></jats:bold> are the extinction distance and the reciprocal lattice vector respectively of the strongly excited reflection. The expression is verified by comparing calculated line‐widths with measured widths from silicon as a function of incident beam energy and reflection excited. An appendix is given discussing quantitatively the degradation effects of beam divergence on electron channelling lines. It is suggested that line broadening might be a possible method for assessing lattice distortions.</jats:p>