Patent Number: 
Section: claims

1. An x-ray apparatus comprising:an electron beam source, emitting an electron beam;a target onto which the electron beam is directed, the electron beam thereby forming a focal spot on the target, wherein the target has a curved target surface;x-ray optics having a focus and structured to collect x-rays emitted from the focal spot, thereby forming an x-ray beam;a sample position to which the x-ray beam is directed;an electrostatic or electromagnetic electron beam deflection device, the deflection device being disposed, structured and dimensioned to move the focal spot on the target in a plane in which the target surface is curved between a first position in which the electron beam is substantially perpendicular to the curved target surface and a second position in which the electron beam is incident on the curved target surface at a flat angle, the focal spot thereby having a size which is smaller at least by a factor F=1.5 than a size of the target,wherein, for the first position, a photon flux density is maximized and, for the second position, a photon flux is maximized. 2. The apparatus of claim 1, wherein the target is a liquid metal jet target. 3. The apparatus of claim 2, wherein, in a direction transverse to a liquid metal jet target propagation direction and transverse to a propagation direction of the electron beam, an extension of the focal spot is smaller at least by a factor FT=2 than an extension of the liquid metal jet target. 4. The apparatus of claim 3, wherein FT=5. 5. The apparatus of claim 1, wherein said curved surface has a radius of curvature R, with 0<R≤10 mm or with 0<R≤1 mm. 6. The apparatus of claim 1, further comprising an electrostatic or electromagnetic electron beam focusing device, suitable for changing a spot area of the focal spot at least by a factor FS=2 or FS=5. 7. The apparatus of claim 6, wherein the electron beam focusing device comprises one or more electromagnetic coils and/or one or more charged electrodes. 8. The apparatus of claim 1, wherein the electron beam deflection device is suitable for moving the focal spot on the target by at least a distance D=50 μm or D=200 μm. 9. The apparatus of claim 1, wherein the electron beam deflection device is suitable for deflecting the electron beam in two independent directions perpendicular to a propagation direction of the electron beam. 10. The apparatus of claim 9, wherein the independent directions are perpendicular to each other. 11. The apparatus of claim 1, wherein the electron beam deflection device comprises one or more electromagnetic coils and/or one or more charged electrodes. 12. The apparatus of claim 1, wherein the x-ray optics comprises a multilayer mirror, a Montel mirror, a Göbel mirror or mirror having a single reflective surface curved with respect to both a sagittal and a meridional direction of incident x-rays and/or capillary x-ray optics. 13. The apparatus of claim 1, wherein the factor F=2 or F=5. 14. The apparatus of claim 1, wherein the x-ray optics is positioned to collect x-rays emitted from the focal spot at essentially 90° with respect to a propagation direction of the electron beam hitting the target. 15. A method for aligning an x-ray apparatus, the x-ray apparatus having an electron beam source emitting an electron beam, a target onto which the electron beam is directed, thus forming a focal spot on that target and x-ray optics for collecting x-rays from a focus thereof, the method comprising the step of:moving the focal spot on the target by deflecting the electron beam with an electric and/or magnetic field until the focal spot overlaps the focus of the x-ray optics. 16. A method for aligning an x-ray apparatus, the x-ray apparatus having an electron beam source emitting an electron beam, a target having a curved target surface onto which the electron beam is directed, thereby forming a focal spot on that target and x-ray optics for collecting x-rays from a focus of those x-ray optics, the method comprising the steps of:a) directing the electron beam to a first position on the target in which the electron beam is substantially perpendicular to the curved target surface; andb) moving the focal spot on the target in a plane in which the target surface is curved from the first position of step a) to a second position on the target at which the electron beam is incident on the curved target surface at a flat angle, the electron beam thereby being deflected using an electric and/or magnetic field and/or a spot area of the focal spot being altered by changing a focusing of the electron beam using an electric and/or magnetic field, wherein a photon flux density of an x-ray beam formed by the x-ray optics is maximized in step a) and a photon flux of the x-ray beam is maximized in step b). 17. The method of claim 16, wherein the curved target surface has a radius of curvature R, with 0<R≤1 mm.