On the association of toroidal and axial magnetic fields for conversion electron spectroscopy

The properties corresponding to the addition of a convergent toroidal magnetic lens between the source and the solenoidal field of an electron-guide are calculated and experimentally tested on a non-optimized present system. The conditions necessary to fully exploit this original association are deduced from this first implementation. It is possible to obtain an improved efficiency on a large energy range, together with a large β+ rejection and an increase of the solid angle freed for a complementary γ-detection.