Patent ID: 7643614

Claim:
An apparatus for generating x-rays comprising: a target substrate; a re-entrant target shaft attached to the target substrate, the re-entrant target shaft having an inner surface and an outer surface, the inner surface positioned to face toward a center of rotation of the target; an emissive coating applied to the target substrate and the inner surface of the target shaft; a bearing cartridge coupled to the re-entrant target shaft and configured to cause the re-entrant target shaft to rotate about the center of rotation, the bearing cartridge comprising: a shaft; a stem; and a bearing assembly rotatably coupling the shaft to the stem; and a receptor extending between the inner surface of the re-entrant target shaft and the stem such that a first gap is formed between the re-entrant target shaft and the receptor and such that a second gap is formed between the stem and the receptor, wherein the receptor is configured to receive a heat transfer from the inner surface of the target shaft.