One-stage probe-forming systems with quadrupole lenses excited by individual power supplies

The work deals with the ion-optical characteristics of the probe-forming systems based on a quadruplet of magnetic quadrupole lenses with four power supplies. The excitation of the lenses of a final doublet of such system is determined from the stigmatic focusing conditions, and the excitations of the first two lenses (downstream the beam) are free parameters which form a parametric set of the probe-forming systems. For this parametric set, the system acceptance reduced to the envelope dimensions in the target plane is determined as a figure of merit for the optimization task. The solution of this task gives optimal excitations of the first two lenses allowing an increase in demagnifications and acceptance of the probe-forming systems with individual power supplies in comparison with a separated Russian quadruplet.