Two-proton decay of 45Fe:: a new type of radioactivity

According to most mass models, several of the best candidates for two-proton radioactivity lie in the A = 50 mass region, at the proton drip-line. Recent experiments using the fragmentation of a 58Ni beam allowed us to reach this region and observe some of these candidates, like 45Fe and 48Ni. During an experiment at the GANIL / LISES facility, decay events correlated to the implantation of 22 ions of 45Fe could be assigned to the direct emission of two protons from the ground state. This decay mode appears through a (1.14 ± 0.04) MeV peak observed in the decay energy spectrum with a half-life of (4.7-1.4+3.4) ms.