On the determination of lattice parameters by the debye-scherrer method

The types of systematic error arising in the determination of lattice parameters by the use of Debye-Scherrer powder diagrams are discussed. The various extrapolation methods are reviewed, and it is shown how a consideration of the absorption factor and geometry of the focal spot lead to the most satisfactory forms of extrapolation curve. It is shown how the absence of specimen eccentricity enables perfectly linear extrapolation curves to be drawn, thus allowing fullest use to be made of low-angle reflexions, whereby the very highest accuracy in parameter determination may be achieved.