Ponente
Descripción
Isotopes close to the doubly-magic nuclei $^{132}$Sn are of strong interest from the point of view of nuclear structure. Spectroscopic studies are performed with the aim of obtaining a better understanding of the evolution of shell orbits in nuclei with large N/Z ratios, and providing critical tests of theoretical models. The information on the nuclear structure and decay properties of n-rich nuclei in this region may also provide input to calculations for astrophysical r-process.
A new experimental camping was carried out at the ISOLDE facility to study the $\beta$-decay of neutron-rich cadmium isotopes. High intensity Cd (Z = 48) beams were produced after the fission of a thick UC$_{x}$ target, selectively ionized by the ISOLDE Resonance Ionization Laser Ion Source (RILIS) and separated in mass using the General Purpose Separator (GPS) ISOLDE mass separator. A temperature-controlled quartz transfer line was used to ensure purity of the cadmiun beams [1].The experiment exploited the excellent spectroscopic capabilities of the ISOLDE Decay Station (IDS). The fast-timing configuration was employed, which included 6 highly efficient clover-type HPGe detectors, altogether with 2 LaBr$_3$(Ce) and 3 ultra-fast $\beta$-plastic detectors arranged in close geometry.
Direct observation of $\gamma$-ray de-excitations and $\gamma$-$\gamma$ coincidences in $^{132}$In has been achieved following the $\beta$-decay of the $^{132}$Cd 0$^+$ ground state (g.s.). The $^{132}$In nuclear structure information is complemented by the $\beta$-n decay of $^{133}$Cd, providing enhanced statistics. These results expand those from experiments at RIKEN facility [2,3].
The significantly higher statistics and the possibility of using coincident $\gamma$-$\gamma$ measurements enable an expanded level scheme and more detailed comparison with shell-model calculations. An interpretation of the level structure is given based on the experimental findings and the particle-hole configurations arising from core excitations both from the N < 82 and Z < 50 shells, leading to positive- and negative-parity particle-hole multiplets [2,3].
[1] Fraile, L. M., \& Korgul, A. \textit{et al.}, (2020). Beta-decay spectroscopy of neutron-rich Cd isotopes (No. CERN-INTC-2020-070).
[2] T. Parry (2023). Structure of Neutron-rich Nuclei in the $^{132}$Sn Region. PhD Thesis, University of Surrey, 2024.
[3] A. Jungclaus \textit{et al.}, (2016). Physical Review C, 93(4), 041301.
