Radiology X=ray tube preventing extra focal absorption - has absorption arc of light material outer layer and high atomic mass inner layer

摘要

The X-ray tube for general radiological use has a disc anode and an absorption section to prevent extra-focal emission. The absorption section consists of an arc covering the general target area(1) but having a tapered hole to allow the electron beam(3) to reach the target surface. The arc absorbing any secondary electrons consists of an outer light material(A) such as graphite or titanium and an inner layer(B) of a high atomic mass material such as tungsten. This absorbs X-ray emission from any point other than the electron beam focus area.