In order to provide an increased, i.e. faster, periodic modulation of X-ray intensity, an anode disk (28) for a rotating anode in an X-ray tube includes a circumferential target area (34) with a target surface area (36), a focal track center line (38), and a beam-dump surface area (40). The target surface area when hit by an electron beam generates X-rays. The beam-dump surface area when hit by an electron beam generates no useful X-rays Target portions and beam-dump portions are arranged alternatingly along the focal track center line. A focal spot is centered on the focal track center line. Structures on both sides of the focal track center line are arranged such that same radiation intensities are provided by the both sides when being hit by a homogenous electron beam.