# Exploring the mass surface near the rare-earth abundance peak via precision mass measurements at JYFLTRAP

## TL;DR

This study used precision mass measurements at JYFLTRAP to explore the neutron-rich rare-earth isotopes, improving understanding of the mass surface and its implications for astrophysical nucleosynthesis near the rare-earth abundance peak.

## Contribution

First-time measurements of 8 neutron-rich rare-earth isotopes and analysis of their impact on the astrophysical r-process and nuclear structure systematics.

## Key findings

- New mass values improve the modeling of the rare-earth abundance peak.
- Enhanced agreement between predicted and solar abundance patterns.
- Insights into neutron pairing and shell effects near the rare-earth region.

## Abstract

The JYFLTRAP double Penning trap at the Ion Guide Isotope Separator On-Line (IGISOL) facility has been used to measure the atomic masses of 13 neutron-rich rare-earth isotopes. Eight of the nuclides, $^{161}$Pm, $^{163}$Sm, $^{164,165}$Eu, $^{167}$Gd, and $^{165,167,168}$Tb, were measured for the first time. The systematics of the mass surface has been studied via one- and two-neutron separation energies as well as neutron pairing-gap and shell-gap energies. The proton-neutron pairing strength has also been investigated. The impact of the new mass values on the astrophysical rapid neutron capture process has been studied. The calculated abundance distribution results in a better agreement with the solar abundance pattern near the top of the rare-earth abundance peak at around $A\approx165$.