Patent Number: 
Section: abstract

The parallel radiation (12) emanating from a sample 4 in a known apparatus for X-ray analysis (for example, for diffraction) is analyzed according to wavelength and focused in a focus 20 by a parabolic multilayer mirror 14. A collimator 28 is positioned around said focus. The resolution of the apparatus can be enhanced by making the angular passage width of the collimator smaller than the maximum range of its reflection angle xcex1max. In accordance with the invention the resolution of the apparatus will be better defined and hence enhanced by implementing the exit collimator 28 in such a way that the angular value for the passage width from every reflecting point A or B of the mirror surface is substantially independent of the position of the reflecting points. Preferably, the exit collimator 28 is implemented in the form of two mutually parallel knife edges which are situated at different distances from the reflecting points of the multilayer mirror.