Binding energies of ground and isomeric states in neutron-rich ruthenium isotopes: measurements at JYFLTRAP and comparison to theory

Abstract

We report on precision mass measurements of ${}^{113,115,117}$Ru performed with the JYFLTRAP double Penning trap mass spectrometer at the Accelerator Laboratory of University of Jyväskylä. The phase-imaging ion-cyclotron-resonance technique was used to resolve the ground and isomeric states in ${}^{113,115}$Ru and enabled for the first time a measurement of the isomer excitation energies, $E_x{(}^{113}$Ru${}^m)=100.5(8)$ keV and $E_x{(}^{115}$Ru${}^m)=129(5)$ keV. The ground state of ${}^{117}$Ru was measured using the time-of-flight ion-cyclotron-resonance technique. The new mass-excess value for ${}^{117}$Ru is around 36 keV lower and 7 times more precise than the previous literature value. With the more precise ground-state mass values, the evolution of the two-neutron separation energies is further constrained and a similar trend as predicted by the BSkG1 model is obtained up to the neutron number $N=71$.

Comments: 12 pages, 9 figures, submitted to Physical Review C