Patent Number: 
Section: claims

1. An x-ray radiation device to generate quasi-monochromatic x-ray radiation, comprising:a punctiform radiation source that emits polychromatic x-ray radiation;a diffraction device on which said polychromatic x-ray radiation is incident, said diffraction device diffracting the polychromatic x-ray radiation incident thereon and having a super-mirror comprised of crystalline material having a flat surface, said crystalline material in said super-mirror having a crystal lattice exhibiting a lattice plane spacing that continuously varies within said crystal lattice;said diffraction device causing quasi-monochromatic x-ray radiation to be generated from a portion of the polychromatic x-ray radiation incident thereon by Bragg reflection at said super-mirror; anda displacement device that displaces said super-mirror in a displacement direction perpendicular to said flat surface, the displacement of said super-mirror in said direction perpendicular to said flat surface changing an energy band in which said quasi-monochromatic x-ray radiation is generated, and thereby allowing selection of said energy band dependent on said displacement. 2. An x-ray radiation device as claimed in claim 1 wherein said lattice plane spacing continuously varies along at least one direction of said flat surface. 3. An x-ray radiation device as claimed in claim 1 wherein said crystalline material has a continuously varying lattice plane spacing in a direction perpendicular to said flat surface. 4. An x-ray radiation device as claimed in claim 1 wherein said polychromatic x-ray radiation incident on said diffraction device, other than said portion reflected at said super-mirror, is transmitted through or absorbed by said diffraction device. 5. An x-ray radiation device as claimed in claim 1 wherein said diffraction device causes generation of said quasi-monochromatic x-ray radiation with a quantum energy between 40 keV and 90 keV. 6. An x-ray radiation device as claimed in claim 1 wherein said crystalline material has a continuously varying lattice plane spacing in at least one direction along said flat surface that gives said super-mirror straight contour lines of said lattice plane spacing on said flat surface. 7. An x-ray radiation device as claimed in claim 6 wherein said straight contour lines are parallel to each other. 8. An x-ray radiation device as claimed in claim 6 wherein said polychromatic x-ray radiation emitted by said radiation source contains a central ray, and wherein said super-mirror is oriented with respect to said radiation source to cause said contour lines to be parallel to a projection of said central ray of the x-ray radiation on the super-mirror. 9. An x-ray radiation device as claimed in claim 1 wherein said crystalline material has said continuously varying lattice plane spacing in at least one direction along said flat surface that gives said super-mirror arcuate contour lines of said lattice plane spacing on said flat surface. 10. An x-ray radiation device as claimed in claim 9 wherein said polychromatic x-ray radiation emitted by said radiation source contains a central ray, and wherein said super-mirror is oriented with respect to said radiation source to cause said contour lines to be parallel to a projection of said central ray of the x-ray radiation on the super-mirror. 11. An x-ray radiation device as claimed in claim 1 wherein said super-mirror is comprised of a combination of materials selected from the group consisting of a combination of nickel and carbon, a combination of molybdenum and silicon, and a combination of tungsten and silicon. 12. An x-ray radiation device as claimed in claim 1 wherein said lattice plane spacing of said crystal lattice of said crystalline material is in a range between 0.02 nm and 0.25 nm. 13. An x-ray radiation device as claimed in claim 1 wherein said super-mirror has a front side on which said polychromatic radiation is incident and a rear side opposite to said front side, and wherein said rear side of said super-mirror comprises a coating of a material that absorbs said polychromatic radiation. 14. An x-ray radiation device as claimed in claim 13 wherein said material is lead. 15. A medical radiography x-ray acquisition system comprising:an x-ray radiation device comprising a punctiform radiation source that emits polychromatic x-ray radiation, a diffraction device on which said polychromatic x-ray radiation is incident, said diffraction device diffracting the polychromatic x-ray radiation incident thereon and having a super-mirror comprised of crystalline material having a flat surface, said crystalline material in said super-mirror having a crystal lattice exhibiting a lattice plane spacing that continuously varies within said crystal lattice, and said diffraction device causing quasi-monochromatic x-ray radiation to be generated from a portion of the polychromatic x-ray radiation incident thereon by Bragg reflection at said super-mirror;a displacement device that displaces said super-mirror in a displacement direction perpendicular to said flat surface, the displacement of said super-mirror in said direction perpendicular to said flat surface changing an energy band in which said quasi-monochromatic x-ray radiation is generated, and thereby allowing selection of said energy band dependent on said displacement; andan x-ray detector located in a path of said quasi-monochromatic x-ray radiation, said x-ray radiation device and said x-ray detector being adapted to receive an examination subject therebetween that is also irradiated by said quasi-monochromatic x-ray radiation, and said x-ray detector generating electrical signals representing said quasi-monochromatic x-ray radiation, in said band, attenuated by the examination subject, in a form allowing generation of an x-ray image of the examination subject therefrom.