High Brightness Electron Gun for X-Ray Source

A new electron-gun system is under development in order to increase X-ray brightness from a rotating target. In commercial X-ray generators, electron beams usually hit targets at the outer part. Owing to deformation by centrifugal force, there has been a limit on electron beam intensities. In order to overcome this difficulty, we proposed a new system that strongly focuses electrons on a rotating target to strike inside of a ring-shape projection. It has an advantage in that heated-up points have supports back side against centrifugal force. It is expected that this merit makes it possible to raise beam intensity to give stronger X-rays with higher brightness. The experiment with a beam has been performed recently. The first result is reported.