Patent Number: 
Section: claims

1. A collimator, for high-energy electromagnetic radiation, comprising a plurality of X-ray optical elements which bound an opening arranged in a beam path including an X-ray optical element at an entrance side and an X-ray optical element at an exit side of the collimator, and a tube having inner walls between the X-ray optical elements at the entrance side and the exit side; wherein the X-ray optical elements are slit or hole diaphragms provided with at least one passage opening for rays; and wherein an edge zone of the X-ray optical element at the entrance side is angled at least partly relative to a direction of propagation of the rays; and the inner walls are of a different material than the diaphragms, wherein at least one of the X-ray optical elements is provided with at least one passage opening for rays, and the edge zone of the X-ray optical element which faces the passage opening is graduated and comprises a zone which is longer in the propagation direction of the rays and has a larger opening and also a subsequent zone in the direction of propagation which is shorter and has a smaller opening. 2. A collimator according to claim 1, wherein the angle of the element at the entrance side is such that a ray which travels at a grazing angle along the angled edge zone of the X-ray optical element at the entrance side is not incident directly on the X-ray optical element at the exit side. 3. A collimator as claimed in claim 1, wherein the X-ray optical elements are arranged at a distance from one another and are provided with respective angulated edge zones. 4. A collimator as claimed in claim 1, wherein the X-ray optical diaphragms enclose the rays in a segment and the collimator is provided on an inner side with walls which reflect or scatter or produce secondary radiation. 5. A collimator as claimed in claim 4, wherein in the collimator there are arranged further diaphragms which bound a beam diameter in order to filter out radiation reflected or scattered by the walls or secondary radiation. 6. A collimator as claimed in claim 1, wherein the X-ray optical diaphragms at the entrance side and the exit side are provided with an angulation of the same orientation. 7. A collimator as claimed in claim 1, wherein an angulation of the element at the exit side is such that a ray which travels at a grazing angle along an angulated edge of the X-ray optical element at the exit side does not originate directly from the X-ray optical element at the entrance side. 8. A collimator as claimed in claim 1 which includes said X-ray optical elements having edge zones at the entrance side and at the exit side.