Speaker
Description
The investigation of $\beta$-decay properties of neutron-rich nuclei in the A $\approx $ 120 region provides essential input for testing modern nuclear-structure models and for constraining astrophysical r-process simulations. In this context, the $\beta^-$ decay of $^{118}$Pd (Z = 46, N = 72) populating excited states in $^{118}$Ag was studied at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the University of Jyväskylä.
The $^{118}$Pd isotopes were produced in proton-induced fission of uranium and
mass- separated using the JYFLTRAP system to ensure isotopic purity. The decay spectroscopy setup consisted of three high-purity germanium detectors for $\gamma$-ray detection, a plastic scintillator for $\beta$ tagging, and a movable tape-transport system for activity collection and removal.
Analysis of $\beta$-$\gamma$ and $\gamma$–$\gamma$ coincidence data resulted in a significant revision of the known decay scheme of $^{118}$Pd [1]. Several new $\gamma$ transitions and previously unobserved excited states in $^{118}$Ag were identified. Moreover, a cascade of transitions potentially feeding a new isomeric state [2] has been proposed. The ongoing analysis includes the determination of $\beta$-feeding intensities and log ft values, which will enable more precise spin–parity assignments and improved modeling of $\beta$-decay strength in this mass region.
These results contribute to the systematic study of neutron-rich palladium and silver isotopes, relevant both for understanding nuclear structure near the N = 70 region and for providing experimental constraints to r-process nucleosynthesis calculations. A review of the most recent results will be given and discussed.
[1] Z. Janas, J. Äystö, K. Eskola, P.P. Jauho, A. Jokinen, J. Kownacki, M. Leino, J.M. Parmonen, H. Penttilä, J. Szerypo, J. żylicz, Nuclear Physics A,
Volume 552, Issue 3,
1993, Pages 340-352,
[2] B. van den Borne, M. Stryjczyk, R. P. de Groote, A. Kankainen, D. A. Nesterenko, L. Al Ayoubi, P. Ascher, O. Beliuskina, M. L. Bissell et al., Phys. Rev. C 111, 014329 – Published 30 January, 2025
| Contribution category | Experiment |
|---|---|
| Presenter status | Student |