Determination of multiple lattice parameters from convergent-beam electron diffraction patterns

A technique is presented to determine multiple lattice parameters from experimental CBED patterns. For ideal cases, this method can be used to find six unknown lattice parameters (a, b, c, α, β and γ) from a single CBED pattern. Measurement error was found to place limitations on the technique, the most important being that a maximum of three lattice parameters can be determined simultaneously from a single CBED pattern. Several alternate methods were explored for simulating CBED patterns; however, these methods can lead to incorrect solutions. A detailed analysis of the lattice parameter error was conducted and a procedure is presented to optimize the lattice parameter precision. Examples are presented for the [114] CBED pattern of aluminium and the [11ovbar|26] CBED pattern of titanium. Limitations of this technique due to symmetry are also discussed.