Total β-decay energies and masses of short-lived isotopes of zinc, gallium, germanium and arsenic

Abstract

Experimental total β-decay energies for short-lived isotopes of zinc, gallium, germanium and arsenic are presented. The sources were produced as mass-separated fission products at the OSIRIS on-line separator at Studsvik. By applying β-γ coincidence methods, Q β values were determined for 75–78Zn, 76–79Ga, 79, 80Ge and 80, 81, 83As. For these nuclei to the shell N = 50 and in the vicinity of the r-process “seed”, the atomic mass excess could be derived, allowing the comparison of masses of very neutron-rich unstable nuclei with predictions from mass formulae.