For more than 20 years

capillary optics have been used in X-ray analytics. During this time the technology of manufacturing capillary optics passed a considerable development. Whereas in the beginning of 1990s assembled capillary optics were tested in research laboratories

at present monolithic polycapillary optics are widely used in commercial X-ray analytical instruments. These optics show capillary sizes in the micrometer region and their physical behaviour can be described in terms of geometrical optics using ray tracing programs. Recently capillary channel sizes of 200 nm and below were realised due to further improvement of the manufacturing technology for polycapillary structures. At such small structures

the appearance of wave effects for X-ray radiation was observed. Finally

application examples for capillary optics in micro X-ray fluorescence analysis and micro X-ray diffractometry are presented.