Disclosed is an X-ray source, including: a cathode; an anode positioned on the cathode so as to face the cathode; emitters formed on the cathode; a gate electrode positioned between the cathode and the anode and including openings at positions corresponding to those of the emitters; an insulating spacer formed between the gate and the anode; and a coating layer formed on an internal wall of the insulating spacer, and including a material having a lower secondary electron emission coefficient than that of the insulating spacer.
1. An X-ray source, comprising:
a cathode;
an anode positioned on the cathode so as to face the cathode;
emitters formed on the cathode;
a gate electrode positioned between the cathode and the anode and including openings at positions corresponding to those of the emitters;
an insulating spacer positioned under the cathode; and
a coating layer formed on an upper surface of the insulating spacer, and including a material having a lower secondary electron emission coefficient than that of the insulating spacer; and
a terminal penetrating the insulating spacer and the coating layer, and electrically connected to the cathode,
wherein the coating layer is only present on a portion of the upper surface that is closer to the cathode.
2. The X-ray source of claim 1 , wherein the coating layer prevents the insulating spacer and the electrons from colliding with each other and secondary electrons from being generated.
3. The X-ray source of claim 1 , wherein the insulating spacer has a plate form.
4. The X-ray source of claim 1 , wherein an exposed surface of the anode is inclined at a non-normal angle with respect to an axis of the cylinder.
5. The X-ray source of claim 1 , wherein a thickness of the coating layer decreases as the coating layer approaches the anode.