TrappedIons.org

G. Martínez-Pinedo

Mass Measurements of Neutron-Rich Gallium Isotopes Refine Production of Nuclei of the First r-Process Abundance Peak in Neutron Star Merger Calculations

M. P. Reiter, S. Ayet San Andrés, S. Nikas [3,4], J. Lippuner [5,6,7], C. Andreoiu [8], C. Babcock [2], B. R. Barquest, J. Bollig [2,9], T. Brunner [2,10], T. Dickel [1,3], J. Dilling [2,11], I. Dillmann [2,12], E. Dunling [2,13], G. Gwinner [14], L. Graham [2], C. Hornung [1], R. Klawitter [2,15], B. Kootte [2,14,12], A. A. Kwiatkowski, Y. Lan [2,11], D. Lascar [2,16,17], K. G. Leach, E. Leistenschneider [2,11,3,4,12,9,1], G. Martínez-Pinedo, J. E. McKay, S. F. Paul, W. R. Plaß, L. Roberts [18], H. Schatz [7,18,19], C. Scheidenberger [1,3], A. Sieverding [3,4,20,2], R. Steinbrügge, R. Thompson [21], M. E. Wieser, C. Will [1], D. Welch [18]

Abstract

We report mass measurements of neutron-rich Ga isotopes $^{80-85}$Ga with TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The measurements determine the masses of $^{80-83}$Ga in good agreement with previous measurements. The masses of $^{84}$Ga and $^{85}$Ga were measured for the first time. Uncertainties between $25-48$ keV were reached. The new mass values reduce the nuclear uncertainties associated with the production of A $\approx$ 84 isotopes by the \emph{r}-process for astrophysical conditions that might be consistent with a binary neutron star (BNS) merger producing a blue kilonova. Our nucleosynthesis simulations confirm that BNS merger may contribute to the first abundance peak under moderate neutron-rich conditions with electron fractions $Y_e=0.35-0.38$.