Graphene serving as cathode of x-ray tube and x-ray tube thereof

A high-efficiency graphene cathode field emission X-ray tube, comprising a cathode assembly, an anode assembly and a vacuum glass tube;

• wherein the anode assembly comprises an anode target, a Kovar ring and an anode handle, and the anode target is formed integral with the anode handle;
• in the high-efficiency graphene cathode field emission X-ray tube, a high voltage is introduced through the anode handle, a graphene cathode is grounded via a Kovar stem, the graphene cathode emits electrons due to the high voltage between an anode and a cathode, a cathode head and a cathode shield are riveted into an equipotential body to serve as a gate electrode of the X-ray tube, a voltage ranging from −2000v to +2000v is applied between the cathode head, the cathode shield and the graphene cathode to control the magnitude of electron emission, and the electrons are accelerated in a high-voltage electric field generated by the high voltage to bombard the anode target so as to generate X-rays;
• and
• a distance D1 between the graphene cathode and a top surface of the cathode shield is 0.5-2.5 mm;
• a distance D2 between the anode target and the cathode is 10 mm-15 mm;
• and the highest voltage is larger than 150 KV.