Fig. 12

Velocity dependent focusing in electrostatic lens. Illustration of the effect that leads to mismatches in the beam density normalization method used here. Panel a a homogeneously filled lens would focus particles as shown by the pink shaded area. Panels b and c because in our case the lens is fed from a curved guide the particles are not symmetrically distributed and the beam will exit the lens at a slight angle that depends on forward velocity and guide voltage