X-ray tube target having electron pervious coating of heat absorbent material on X-ray emissive surface

摘要

An X-ray tube including a tubular envelope having rotatably mounted therein an anode target disc provided with an annular focal track made of X-ray emissive material having an atomic number greater than forty and coated with a heat absorbent layer having a thickness in the range of 2 to 50 micrometers and made of an elemental or a compound material, comprising one or more elements having respective atomic numbers no greater than thirty.