X-ray tube

摘要

X-ray tube capable of preventing electric corrosion and exerting stable performance over long periods. The X-ray tube includes: a rotary anticathode (1) having a rotary anticathode part (1a) and a shaft part (1b); an anticathode accommodating case (2) including an air-tight case part (2a) for keeping an area surrounding the rotary anticathode part in a vacuum atmosphere, and a journaling case part (2b) for rotatively supporting the shaft part via a bearing; and an electric motor to rotatably drive the anticathode (target). A water-cooled jacket (7), through which cooling water for cooling the rotary anticathode part and the shaft part flows, is provided in the rotary anticathode. In the X-ray tube, an insulating bearing (18) of which at least one of an inner ring (18a), an outer ring (18b) and a rolling element (18c) is made of an insulating material is used as the bearing, and a conductive fiber brush (20) having a large number of conductive microfibers (22) serving as slide-contacting brush is arranged between opposing peripheral surfaces of the journaling case part of the anticathode accommodating case and the shaft part of the rotary anticathode, such that current is flown from the rotary anticathode to the anticathode accommodating case via the conductive fiber brush (20). In addition, pure water or ion-exchange water having low electric conductivity is used as cooling water flown through the water-cooled jacket.