Parafocusing Properties of Microcrystalline Powder Layers in X-Ray Diffraction Applied to the Design of X-Ray Goniometers

A distinction is drawn between the focusing properties of single crystals with regard to x-ray diffraction and the parafocusing properties of microcrystalline powder layers. A discussion of these parafocusing properties and of the absorption term, which arises in the diffraction of x-rays from powder layers, is followed by a discussion of various types of powder goniometers. Their characteristic properties are compared. The application of parafocusing conditions to the design of a goniometer for quantitative evaluations and of back reflection cameras is discussed in greater detail.