The Lorentz-polarization factor and preferred orientation in oriented clay aggregates

Abstraet--A closed-form equation was derived that describes the powder-ring distribution factor as a function of 20, soller slit collimation, and or*, which is defined as the standard eviation of an axiaUy symmetrical Gaussian orientation function. Methods were developed for measuring a * in the reflection mode by means of a 0/20 diffractometer. Six experimental arrangements for a sedimentary chlorite showed widely different i tensity ratios of the 001/005 reflections a d gave a standard deviation of • 5.8 % when corrected by the theory. The absolute integrated intensities ofthe 003 reflection from eleven illite samples provided an eight-fold maximum range which, when corrected, yielded a standard eviation of • The intensity distributions within each of two X-ray powder diffraction patterns obtained from instru-ments with different soller-slit configurations could not be directly compared at low diffraction angles unless corrections, based on a*, were introduced to allow for the differences in axial divergence