Measuring the positron affinities of atoms

It is proposed that the binding energies of positrons to a number of atoms be determined by the charge transfer reaction A(-)+e(+) --> Ae(+)+e(-). Thi s reaction can be realized in the laboratory by directing a negative ion be am through a positron trap and measuring positively charged ions downstream . Unique identification of Ae(+) is possible when the electron affinity, po sitron affinity and neutral atom ionization potentials satisfy a few simple identities. This technique could be used to investigate the existence of p ositron binding for a number of elements such as Si, Fe, Cu, Ge, Ru, Ag, Sn , Sb, Ta, W,Au, Pb and Bi.