Approaching the N=82 shell closure with mass measurements of Ag and Cd isotopes

Abstract

Mass measurements of neutron-rich Cd and Ag isotopes were performed with the Penning trap mass spectrometer ISOLTRAP. The masses of Ag-112,Ag-114-124 and Cd-114,Cd-120,Cd-122-124,Cd-126,Cd-128, determined with relative uncertainties between 2 x 10(-8) and 2 x 10(-7), resulted in significant corrections and improvements of the mass surface. In particular, the mass of Ag-124 was previously unknown. In addition, other masses that had to be inferred from Q values of nuclear decays and reactions have now been measured directly. The analysis includes various mass differences, namely the two-neutron separation energies, the applicability of the Garvey-Kelson relations, double differences of masses delta V-pn, which give empirical proton-neutron interaction strengths, as well as a comparison with recent microscopic calculations. The delta V-pn results reveal that for even-even nuclides around Sn-132 the trends are similar to those in the Pb-208 region.