The present invention relates to a device for generating X-rays having a source for emitting electrons, a carrier which is provided with a material which generates X-rays as a result of the incidence of electrons, and a bearing by means of which the carrier is journalled so as to be rotatable about an axis of rotation, the device further having a chamber that is bounded by a heat transferring surface of the carrier and by a heat transferring surface of the first bearing member, and that is at least partially filled with a heat transferring material, the material being urged, during operation, towards both heat transferring surfaces so that a relatively high rate of heat transfer is obtained between the heat transferring surfaces and the transferring material, which is not affected when the transferring surfaces thermally deform at relatively high temperatures because the transferring material will follow deformations of the heat tranferring surfaces such that the reduction of the overall rate of heat transfer is limited.