An x-ray detector includes a large number of pixels, each of the latter being configured from one or more sub-pixels. Each of the sub-pixels include a detector material for the direct conversion of incident X-ray radiation into an electric signal. A device for converting the electric signals into corresponding digital signals is associated with each of the sub-pixels and the detector is also equipped with a device for processing said digital signals into a combined digital signal representing the number and/or energy of the X-ray quanta that are incident on the pixel.