LABORATORI NAZIONALI DI LEGNARO
A new electrostatic quadrupole triplet lens design is being implemented for the low-energy beam transport system of the SPES facility under construction at the INFN Legnaro National Laboratories. Results of early prototype testing are presented here, as well as complementary simulations of vacuum performance and beam transport. The design process led to an interesting result that “violates” an age-old rule-of-thumb for quadrupole design: when using cylindrical electrodes, the optimal electrode radius is 1.145a, where a is the quadrupole aperture radius. We have found that increasing this value reduces the spherical aberration that results from truncating the cylinders. Accordingly, the mechanical design were finally defined in agreement with these results allowing defining the layout of the 1+ beam line.