We determined the bulk electronic structure in the prototypical Heusler
compound Cu2MnAl by measuring the Angular Correlation of Annihilation
Radiation (2D-ACAR) using spin-polarized positrons. To this end, a new
algorithm for reconstructing 3D densities from projections is introduced that
allows us to corroborate the excellent agreement between our electronic
structure calculations and the experimental data. The contribution of each
individual Fermi surface sheet to the magnetization was identified, and summed
to a total spin magnetic moment of 3.6±0.5μB/f.u.