Layer thickness determinations with X-ray diffraction

A new equation involving an absorption coefficient is presented for calculating the thickness of a layer of a crystalline specimen deposited on a crystalline substrate. This new equation is particularly applicable to in situ X-ray diffraction studies of diffusion-limited kinetics; it is demonstrated that the practical difficulty of optimally partitioning count time between the peak of the substrate and peak of the layered specimen is overcome by making use of all available data in this single equation. This can result in more precise thickness determinations for intermediate specimen thicknesses than would be possible with either of the existing methods.