Probing the N = 104 midshell region for the r process via precision mass spectrometry of neutron-rich rare-earth isotopes with the JYFLTRAP double Penning trap

Le résumé fourni par la source

We have performed high-precision mass measurements of neutron-rich rare-earth Tb, Dy, and Ho isotopes using the phase-imaging ion-cyclotron-resonance technique at the JYFLTRAP double Penning trap. We report on the first experimentally determined mass values for $^{169}\mathrm{Tb}$, $^{170}\mathrm{Dy}$, and $^{171}\mathrm{Dy}$, as well as the first high-precision mass measurements of $^{169}\mathrm{Dy}$ and $^{169--171}\mathrm{Ho}$. For $^{170}\mathrm{Ho}$, the two long-lived ground and isomeric states were resolved and their mass measured, yielding an isomer excitation energy of ${E}_{\text{exc}}=150.8(54)$ keV. In addition, we have performed independent crosschecks of previous Penning-trap values obtained for $^{167\text{,}168}\mathrm{Tb}$ and $^{167\text{,}168}\mathrm{Dy}$. We have extended the systematics of two-neutron separation energies to the neutron midshell at $N=104$ in all of the studied isotopic chains. Our updated and new mass measurements provide better mass-related constraints for the neutron-capture reaction rates relevant to the astrophysical rapid neutron capture $(r)$ process. The $r$-process abundances calculated with the new mass values seem to produce a steeper minimum at $A=170$ and differ by around 15--30% from the abundances computed with the Atomic Mass Evaluation 2020 values.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.