The half‐widths of Bragg intensity profiles measured with a triple‐crystal diffractometer at a synchrotron‐radiation source. I. Derivation of a simple expression for the full width at half‐maximum

On the basis of the expressions given by Rossmanith [ Acta Cryst. (1992), A 48 , 596–610; (1993), A 49 , 80–91], a simple approximation is derived for the half‐widths of Bragg intensity profiles measured with a triple‐crystal diffractometer at a synchrotron‐radiation source. This new formula facilitates insight into the effects of four parameters – divergence, wavelength spread, mosaic spread and mosaic block size – on the widths of the profiles.