Patent Number: 058928090
Section: abstract

A system for local excitation by monochromatic X-rays having a plurality of x-ray sources and a plurality of focussing diffractors to selectively monochromatize X-rays and focus them on a particular region of a sample to be analyzed. The X-ray source for each diffractor is selected from a plurality of closely-spaced sources by displacement of the focal spot of an electron beam that produces the X-rays. Each diffractor is prealigned to focus X-rays generated by the electron beam onto a common region of the sample. Each diffractor comprises a toroidally shaped crystal structure, which, along with the appropriate source and the common region of the specimen satisfies the Johann or Johansson geometric conditions within a plurality of planes containing both the source of X-rays and the focused X-ray image. Application of the system for local excitation to X-ray fluorescence analysis is described.