Abstract: A focal spot having an annular shape is often formed on the an (4) of an X-ray tube for analytic purposes. For the cooling of an anode it is known to force the cooling water to impinge on the anode with a flow profile having the same shape as the focal spot. In order to achieve this effect in the case of an annular focal spot, a circular delivery opening (36) is provided. In order to break up the steady boundary layer on the surface to be cooled, the impinging cooling water is forcibly split so as to flow into two directions. This is achieved by making the water flow via a distribution member 30 in which the circular delivery opening 36 is provided and by discharging the water via a discharge opening 40 which is situated within the circular delivery opening 40 and also via a return opening which is defined by the outer surface 42 of the distribution member 30 and the inner side of the discharge tube 16.