Abstract: A cold emitter x-ray tube is provided comprised of a cathode which is a carbon nanotube or nanostructured carbon film which serves as the electron emission source in an x-ray tube, and is positioned on a suitable substrate. The nanostructured carbon film is selected from a group consisting of nanocyrstalline graphite, carbon nanotubes, diamond, diamond like carbon, or a composite of two or more of members of the group. An extraction/suppression grid may be utilized. A metal anode which functions as the x-ray generating target is positioned within the x-ray tube. A high voltage source with negative contact is connected to the emitter and the positive contact connected to the anode target. This single source of high potential serves to provide the electric field, between the emitter and anode, for extraction of electrons from the emitter and to accelerate the electrons to the target for generation of x-rays. X-rays pass through a beryllium window that is an integral part of the vacuum envelope.