A new parafocusing paradigm for X-ray diffraction.

A new approach to parafocusing X-ray diffraction implemented with an annular incident beam is demonstrated for the first time. The method exploits an elliptical specimen path on a flat sample to produce relatively high intensity maxima that can be measured with a point detector. It is shown that the flat-specimen approximation tolerated by conventional Bragg-Brentano geometries is not required. A theoretical framework, simulations and experimental results for both angular- and energy-dispersive measurement modes are presented and the scattering signatures compared with data obtained with a conventional pencil-beam arrangement.