The position of a scanner and its influence on the beam spot size in a nuclear microprobe

Once focused, the ion beam in a microprobe can be scanned over the sample by using a set of two orthogonal magnetic coils or electrostatic deflection plates positioned before, inside or after the focusing system. In the paper the influence of the scanner position on the beam spot shape is considered for different focusing systems such as triplet, quadruplet and sextuplet and for two different emittances of the beam. The numerous graphs show the dependence of the shape of the spot and the density distribution of the beam on the scanning radius.