X-ray tube, x-ray analysis apparatus, and method of cooling target in x-ray tube

An X-ray tube, comprising:

• an electron-beam emitting unit configured to emit an electron beam;
• a target having a first surface against which the electron beam collides and a second surface on a side opposite to the first surface;
• a solid heat diffusion member fixed onto the second surface of the target;
• and
• a flow-path forming member, which is arranged on a side of the solid heat diffusion member, the side being opposite to the target, and that is configured to define a film flow path in which a cooling fluid forms a film flow,
• wherein the solid heat diffusion member forms a protruding portion protruding toward the side of which is opposite to the target, a center of the protruding portion overlaps a heat generation center at which the electron beam collides against the target to generate heat when viewed in a direction of emission of the electron beam, and
• wherein the film flow path has a shape extending along at least a part of a surface of the protruding portion.