Patent Number: 
Section: claims

1. A collimator having an adjustable focal length for an X-ray inspection system, the collimator comprising:an outer part having a conical inner surface;an inner part having a conical outer surface, the outer part and the inner part being connected to one another at a fixed distance; andat least one cone sliding part movably arranged between the inner part and the outer part. 2. The collimator according to claim 1, wherein all conical surfaces are arranged concentrically about a common axis of rotation. 3. The collimator according to claim 1, wherein all conical surfaces have the same aperture angle α. 4. The collimator according to claim 1, wherein pairs of adjacent conical surfaces have the same aperture angle. 5. The collimator according to claim 1, wherein the at least one cone sliding part travels in a direction of an axis of rotation. 6. A method for adjusting a focal length of a collimator, the method comprisingproviding a collimator for an X-ray system, the collimator having an outer part having a conical inner surface, an inner part having a conical outer surface, the outer part and the inner part being connected to one another at a fixed distance, and at least one cone sliding part movably arranged between the inner part and the outer part; andmoving the at least one cone sliding part along an axis of rotation until a desired focal length is achieved,wherein, when multiple cone sliding parts are used, they are moved independently of one another. 7. An x-ray inspection system comprising:an X-ray source;an X-ray detector;an X-ray detector and an analysis device for analyzing detected radiation; anda collimator with an adjustable focal length, the collimator comprising:an outer part having a conical inner surface;an inner part having a conical outer surface, the outer part and the inner part being connected to one another at a fixed distance; andat least one cone sliding part movably arranged between the inner part and the outer part.