Lens design for large-area x-ray sensitive vidicons

Large-area x-ray sensitive vidicons have the potential to be superior to conventional x-ray image intensifiers for medical fluoroscopy. To build a large-area x-ray vidicon, an electron lens system is necessary to provide perpendicular beam landing. In this paper, we discuss theoretically how to build two and three cylinder coaxial lenses for this purpose. Some general design rules and a preferred design which satisfies our design criteria are presented. Limitations of these simple types of electron lens are discussed. Two advanced designs for vidicons with short lengths or reduced beam landing error are also included. Among them, the deflection-center-change system is introduced here for the first time.