Element R and D for X-ray generator electron gun

A new electron-gun system is under development in order to increase X-ray brightness from a rotating target. In commercial X-ray generators, an electron beam hits a target at outside. Owing to deformation by centrifugal force, there has been a limit on the electron beam intensity. In order to overcome this difficulty, our new system focuses electrons inside of a rotating target. It has an advantage in that a heated-up point has support back side against centrifugal force. It is expected that this merit makes it possible to raise beam brightness to give stronger X-rays with brightness more than 10 times higher. We succeeded in focusing an electron beam of 60keV, 73mA as small as 2.1x0.24 mm2. (author)