Estimation of the mosaic spread and the mosaic‐block size of zinc single‐crystal spheres by simulations of ψ scans with UMWEG 90

In a previous paper [Rossmanith (1992). Acta Cryst. A 48 , 596–610], new formulae for the Lorentz factor and peak width for single and multiple diffraction were given. These formulae are used in the program UMWEG 90 for the calculation of ψ ‐scan simulations. In this paper, simulations are compared with five different ψ scans of two different zinc single‐crystal spheres measured with Mo and Ag Kα radiations, respectively. It is shown that, by fitting the calculated to the measured ψ scans, consistent and physically significant parameters for the mosaic structure parameters – mosaic spread and mosaic block size – and for the divergence parameters of the X‐ray beam are obtained. Moreover, it is shown that the parameters obtained from multiple‐diffraction experiments are consistent with those resulting from single‐diffraction experiments performed with synchrotron radiation.