Ah. Azbaid et al., Electrostatic Russian quadruplet with high demagnification and minimum influence of geometric aberrations, J ELEC MICR, 49(1), 2000, pp. 143-148
Based on a combined analytical and numerical modelling, a high-quality prob
e-forming system is proposed and developed. The Matrizant method is applied
to minimize the beam spot size for a fixed beam current. For quadrupoles c
onsisting of four metallic rods, the electric field inside of the quadruple
t is computed using an accurate version of the boundary element method. The
influence of the rod diameter on the beam spot size is studied for differe
nt emittances. The sensitivity of the system to energy spread and mechanica
l defects is also investigated.