einzel lens

An electrostatic lens that has the same potential at the entrance and exit of the lens. Normally, the "einzel lens" consists of three electrodes. Two electrodes at both ends are set at the ground potential, and a positive or negative potential is given to the central electrode. The lens with a positive potential at the central electrode is called the acceleration-type einzel lens, whereas the lens with a negative potential is called the deceleration-type einzel lens. Both are convex lenses. The electrons passing through the einzel lens undergo lens action without acceleration and deceleration at the exit of the lens. This lens is used for ion-beam instruments, for example, an ion mass analyzer.

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