Speaker
Sabine Boenig
(IKP TU Darmstadt)
Description
The neutron-rich cadmium nuclei with a proton number of Z=48 are some of the most interesting isotopes in nuclear structure physics due to the proximity to the proton and neutron shell closures at Z=50 and N=82 respectively. The excitation energy of the 2_1⁺-states shows an irregular behaviour when approaching the neutron shell closure. From 124Cd to 126Cd the energy is only slightly increasing and from 126Cd to 128Cd even a drop can be noticed. So far this finding can not be reproduced by shell-model (SM) calculations although the shell closure is near. Only Beyond-Mean-Field (BMF) calculations with a resultant prolate deformation agree with the low excitation energy of 128Cd. The transition strength B(E2, 0gs⁺→2_1⁺) in the even isotopes 122-128Cd was measured in Coulomb excitation experiments (IS411, IS477) with MINIBALL at REX-ISOLDE (CERN). Since the values for 122,124Cd coincide with BMF calculations with a resultant prolate deformation 126Cd is better described via SM calculations. Results of the more recent experiment on 128Cd will pursue the picture of the behaviour of the transition strength towards the neutron shell closure. A closer insight into the onset of collectivity and the roles played by different orbits can be obtained by the investigation of the odd isotopes. We started this program with the examination of 123Cd (IS524) where already discrepancies to the literature were evidenced. In this contribution the latest results of the investigation of the B(E2, 0_gs⁺→2_1⁺) values of the even 122-128Cd nuclei as well as first findings from the recently performed measurement of 123Cd via Coulomb excitation will be presented. This project is supported by BMBF (No. 06 DA 9036I and No. 05 P12 RDCIA), HIC for FAIR, EU through EURONS (No. 506065) and ENSAR (No. 262010) and the MINIBALL and REX-ISOLDE collaborations.
Author
Sabine Boenig
(IKP TU Darmstadt)
Co-authors
Anna-Lena Hartig
(IKP TU Darmstadt)
Christopher Bauer
(Technische Universitaet Darmstadt (DE))
Corinna Henrich
(IKP TU Darmstadt)
Marcus Scheck
(University of the West of Scotland, Paisley)
Michael Thuerauf
(Technische Universitaet Darmstadt (DE))
Stoyanka Ilieva
(IKP TU Darmstadt)
Thorsten Kroell
(Technische Universitaet Darmstadt (DE))
