Recent advances in x-ray detectors for TEM and STEM instruments have resulted in large increases in the solid angle that these detectors subtend with respect to the sample. These solid angles of order 0.2 steradian mean that x rays emitted into a cone of semi-angle equal to 15° will be intercepted by the detector. Since the conventional absorption correction for x-ray analysis assumes that all detected rays are parallel, we chose to examine whether divergent x rays could change the absorption and fluorescence corrections significantly and should therefore be taken into account.This paper will focus on the effects of such changes on the absorption correction of thin specimens. Two specimen geometries will be considered, namely the usual plane parallel slab and the sphere geometry. Sphere geometries are of interest because they are currently used in the evaluation of the efficiency of x-ray detectors, the results of which are to be presented in the X-ray Optics and Microanalysis Conference in Poland this summer.
State-of-the-art X-ray optics for in-house crystallography and synchrotrons