X-RAY TUBE WITH HEATABLE FIELD EMISSION ELECTRON EMITTER AND METHOD FOR OPERATING SAME

摘要

An X-ray tube, a medical X-ray device comprising such X-raytube and a method for operating such X-ray tube are proposed. The X-ray tube (1) comprises an electron emitter (3) with a substrate (4) having an electron emission surface (5). The electron emission surface (5) is adapted for field emission of electrons therefrom by providing a substantial roughness. Such roughness may be obtained by applying carbon nano-tubes (19) onto the electron emission surface (5). A field generator (7) is provided for generating an electrical field adjacent to the electron emission surface (5) for inducing field emission of electrons therefrom. Furthermore, a heater arrangement (15) is provided and adapted for heating the electron emission surface (5) contemporaneous with the field emission of electrons. Accordingly, while electrons are emitted from the electron emission surface (5) due to a field effect, this electron emission surface (5) may also be heated to substantial temperatures of between 100 and 1000°C. It has been observed that such heating may stabilize electron emission characteristics as the emitter (3)as adsorbents or contaminations to the carbon nano- tubes may be reduced.