Determination of the geometric blurring of an energy dispersive X-ray diffraction (EDXRD) system and its use in the simulation of experimentally derived diffraction profiles

A computational model has been developed to calculate the geometric blurring distribution of an energy dispersive X-ray diffraction (EDXRD) system. The scattering volume, trapezoid in the horizontal plane, is divided into typically of the order 10(4) elements and the blurring contribution of each element considered in an iterative procedure to build up a distribution for the entire trapezoid. The resultant distribution is asymmetric and peaks at an angle below that nominally set. A correction for the focal spot intensity distribution has been included. The blurring distribution has been used as a filter to the Joint Committee on Powder Diffraction Standards (JCPDS) data for several materials to predict the experimentally derived diffraction profiles. A good agreement has been demonstrated between the simulated and measured spectra with a significant improvement on previous models assuming a Gaussian blurring distribution. The model can be used to predict the spectral blurring for any EDXRD system irrespective of the application.