Speaker
Description
Isotopes close to the doubly-magic nuclei 132Sn are of strong interest from the point of view
of nuclear structure. Spectroscopic studies are performed with the aim of obtaining a better un-
derstanding 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 β-decay
of neutron-rich cadmium isotopes. High intensity Cd (Z = 48) beams were produced after the
fission of a thick UCx 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 LaBr3(Ce) and 3 ultra-fast β-plastic detectors arranged in
close geometry.
Direct observation of γ-ray de-excitations and γ-γ coincidences in 132In has been achieved fo-
llowing the β-decay of the 132Cd 0+ ground state (g.s.). The 132In nuclear structure information
is complemented by the β-n decay of 133Cd, providing enhanced statistics. These results expand
those from experiments at RIKEN facility [2,3].
The significantly higher statistics and the possibility of using coincident γ-γ measurements enable
an expanded level scheme and more detailed comparison with shell-model calculations. An inter-
pretation 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].
