An X-ray source (10) for generating X-rays (11) is provided. The X-ray source (10) comprises an emitter arrangement (12) for generating electrons or for generating X-rays, at least one feedthrough (38) for supplying electrical power to the emitter arrangement (12), and an insulator (20) configured for isolating an electrical potential of the at least one feedthrough (38) from a ground potential. Therein, the at least one feedthrough (38) extends at least partly through the insulator (20), and at least a part of the insulator (20) is in thermal contact with at least a part of the emitter arrangement (12). Further, the insulator (20) comprises at least one cooling channel (28) formed completely in an interior volume (25) of the insulator (20) and configured to dissipate heat from the emitter arrangement (12), wherein a distance (29) between an outer surface (26) of the insulator (20) and the cooling channel (28) is at least as large as half of a thickness (27) of the cooling channel (20).