Examining the nuclear mass surface of Rb and Sr isotopes in the A≈104 region via precision mass measurements
| Autor: | Gerald Gwinner, T. Brunner, Erich Leistenschneider, Y. Lan, E. Dunling, A. Jacobs, Moritz P. Reiter, B. Kootte, Corina Andreoiu, C. Izzo, A. A. Kwiatkowski, S. F. Paul, D. Fusco, Maxime Brodeur, Ish Mukul, K. A. Dietrich, Eleni Marina Lykiardopoulou, Jens Dilling, Timo Dickel, Julian Bergmann, Iris Dillmann, J. L. Tracy |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
Mass excess Isotope 010308 nuclear & particles physics Nuclear Theory Nuclear structure 01 natural sciences 7. Clean energy Nuclear physics 13. Climate action Pairing 0103 physical sciences Nuclear astrophysics Neutron Sensitivity (control systems) Nuclear Experiment 010306 general physics Energy (signal processing) |
| Zdroj: | Mukul, I, Andreoiu, C, Bergmann, J, Brodeur, M, Brunner, T, Dietrich, K A, Dickel, T, Dillmann, I, Dunling, E, Fusco, D, Gwinner, G, Izzo, C, Jacobs, A, Kootte, B, Lan, Y, Leistenschneider, E, Lykiardopoulou, E M, Paul, S F, Reiter, M P, Tracy Jr, J L, Dilling, J & Kwiatkowski, A A 2021, ' Examining the nuclear mass surface of Rb and Sr isotopes in the A≈104 region via precision mass measurements ', Physical Review C, vol. 103, no. 4, 044320, pp. 103 . https://doi.org/10.1103/PhysRevC.103.044320 |
| ISSN: | 2469-9993 2469-9985 |
| Popis: | Background: The neutron-rich $A\ensuremath{\approx}100, N\ensuremath{\approx}62$ mass region is important for both nuclear structure and nuclear astrophysics. The neutron-rich segment of this region has been widely studied to investigate shape coexistence and sudden nuclear deformation. However, the absence of experimental data of more neutron-rich nuclei poses a challenge to further structure studies. The derivatives of the mass surface, namely, the two-neutron separation energy and neutron pairing gap, are sensitive to nuclear deformation and shed light on the stability against deformation in this region. This region also lies along the astrophysical $r$-process path, and hence precise mass values provide experimental input for improving the accuracy of the $r$-process models and the elemental abundances.Purpose: (a) Changes in deformation are searched for via the mass surface in the $A=104$ mass region at the $N=66$ mid-shell crossover. (b) The sensitivity of the astrophysical $r$-process abundances to the mass of Rb and Sr isotopic chains is studied.Methods: Masses of radioactive Rb and Sr isotopes are precisely measured using a Multiple-Reflection Time-of-Flight Mass Separator (MR-TOF-MS) at the TITAN facility. These mass values are used to calculate two-neutron separation energies, two-neutron shell gaps and neutron pairing gaps for nuclear structure physics, and one-neutron separation energies for fractional abundances and astrophysical findings.Results: We report the first mass measurements of $^{103}\mathrm{Rb}$ and $^{103--105}\mathrm{Sr}$ with uncertainties of less than 45 keV/${c}^{2}$. The uncertainties in the mass excess value for $^{102}\mathrm{Rb}$ and $^{102}\mathrm{Sr}$ have been reduced by a factor of 2 relative to a previous measurement. The deviations from the AME extrapolated mass values by more the 0.5 MeV have been found.Conclusions: The metrics obtained from the derivatives of the mass surface demonstrate no existence of a subshell gap or onset of deformation in the $N=66$ region in Rb and Sr isotopes. The neutron pairing gaps studied in this work are lower than the predictions by several mass models. The abundances calculated using the waiting-point approximation for the $r$ process are affected by these new masses in comparison with AME2016 mass values. |
| Databáze: | OpenAIRE |
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