Coulomb excitation of Cu-68,Cu-70: First use of postaccelerated isomeric beams

We report on the first low-energy Coulomb excitation measurements with radioactive $I^{\pi}=6^-$ beams of odd-odd nuclei $^{68,70}$Cu. The beams were produced at ISOLDE, CERN and were post-accelerated by REX-ISOLDE to 2.83 MeV/nucleon. $\gamma$ rays were detected with the MINIBALL spectrometer. The $6^-$ beam was used to study the multiplet of states ($3^-, 4^-, 5^-, 6^-$) arising from the $\pi^2p3/2\nu1g9/2$ configuration. The $4^-$ state of the multiplet was populated via Coulomb excitation and the $B(E2;6^- \to 4^-$) value was determined in both nuclei. The results obtained illustrate the fragile stability of the Z=28 shell and N=40 subshell closures. A comparison with large-scale shell-model calculations using the $^56$Ni core shows the importance of the proton excitations across the Z=28 shell gap to the understanding of the nuclear structure in the neutron-rich nuclei with N$\sim$40

Coulomb Excitation of 68,70Cu: First Use of Postaccelerated Isomeric Beams

We report on the first low-energy Coulomb excitation measurements with radioactive Ipi=6- beams of odd-odd nuclei 68,70Cu. The beams were produced at ISOLDE, CERN and were post-accelerated by REX-ISOLDE to 2.83 MeV/nucleon. gamma rays were detected with the MINIBALL spectrometer. The 6- beam was used to study the multiplet of states (3-, 4-, 5-, 6-) arising from the pi2p3/2nu1g9/2 configuration. The 4- state of the multiplet was populated via Coulomb excitation and the B(E2;6--->4-) value was determined in both nuclei. The results obtained illustrate the fragile stability of the Z=28 shell and N=40 subshell closures. A comparison with large-scale shell-model calculations using the 56Ni core shows the importance of the proton excitations across the Z=28 shell gap to the understanding of the nuclear structure in the neutron-rich nuclei with N[approximate]40

Coulomb Excitation of Neutron-Rich Zn Isotopes: First Observation of the 2[sub 1][sup +] State in [sup 80]Zn

Neutron-rich, radioactive Zn isotopes were investigated at the Radioactive Ion Beam facility REX-ISOLDE (CERN) using low-energy Coulomb excitation. The energy of the 21+ state in 78Zn could be firmly established and for the first time the 2+-->01+ transition in 80Zn was observed at 1492(1) keV. B(E2,21+-->01+) values were extracted for 74,76,78,80Zn and compared to large scale shell model calculations. With only two protons outside the Z=28 proton core, 80Zn is the lightest N=50 isotone for which spectroscopic information has been obtained to date. Two sets of advanced shell model calculations reproduce the observed B(E2) systematics. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78Ni

Coulomb excitation of the N=50 nucleus Zn-80

Neutron rich Zinc isotopes, including the N=50 nucleus Zn-80, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2(+) states. For the first time, an excited state in Zn-80 was observed and the 2(1)(+) state in Zn-78 was established. The measured B(E2,2(1)(+) -> 0(1)(+)) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus Ni-78

Investigation of the Li-9+H-2 -> Li-8+t reaction at REX-ISOLDE

The one-neutron transfer reaction Li-9 + H-2 -> Li-8 + t has been investigated in an inverse kinematics experiment by bombarding a deuterated polypropylene target with a 2.36 MeV/u Li-9 beam from the post-accelerator REX-ISOLDE at CERN. Excitation energies in Li-8 as well as angular distributions of the tritons were obtained and spectroscopic factors deduced. (c) 2006 Elsevier B.V. All rights reserved

Quadrupole collectivity of neutron-rich nuclei around 132Sn

We report on the ``safe'' Coulomb excitation of neutron-rich Cd, Xe, and Ba isotopes in the vicinity of the doubly-magic nucleus 132Sn. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The gamma-decay of excited states has been detected by the MINIBALL array. The presented preliminary results for the B(E2) values are consistent with expectations from phenomenological systematics and will be compared with theoretical calculations.Book subtitle: FINUSTAR 2status: publishe