On the measurement of dislocation core periods by nanodiffraction

Multiple-scattering calculations are used to demonstrate that the periodici ty of dislocation cores may be measured from coherent convergent beam patte rns obtained using a subnanometre probe with the electron beam aligned with the dislocation core. The resulting 'half-order' high-order Laue zone ring which results front a double-period core reconstruction is shown to be det ectable above the background of thermal diffuse scattering. Multiple-scatte ring calculations which include thermal scattering are used to show the tem perature and thickness dependences of this ring. Activation energies for co re processes may be obtained by this method.