An electrostatic objective lens for focusing ion beams to very small diameters on a plane, conducting sample surface was designed. The lens can focus ions of either polarity in the decel-accel or accel-decel mode and collect and collimate secondary charged particles of either polarity emitted with low initial energy. Moreover, a microscopic mirror objective for visual observation of the sample surface in situ is incorporated in the electrostatic optics.
Liebl, H. and Weiss, H.
"Ion Optics of Submicron Ion Beams,"
Scanning Electron Microscopy: Vol. 1986
, Article 1.
Available at: https://digitalcommons.usu.edu/electron/vol1986/iss3/1