A schematic representation of the arrangement of the diffraction geometry. ω is the angle between the incoming beam direction and the specimen surface, θhkl is the Bragg angle of the hkl reflection, ehkl is the normal unit vector of the hkl planes, and θ − ω is the angle between ehkl and the normal of the measured specimen surface, z. The y coordinate lies on the specimen surface. The dashed cone indicates schematically the angular range, 2Δθhkl, within which the hkl reflecting planes correspond to the same texture component. The 2Δθhkl values are correlated to the value of m.r.d.