Probing the nuclear structure in the vicinity of ⁷⁸Ni

¹ University of Oslo, Department of Physics, Oslo, Norway
² Laboratori Nazionali di Legnaro dell’INFN, Legnaro, Italy
³ University of Surrey, Department of Physics, Surrey, UK
⁴ Heavy Ion Laboratory, University of Warsaw, Poland

^* e-mail: eda.sahin@fys.uio.no

Published online: 4 December 2019

Abstract

Theoretical and experimental studies of neutron-rich nuclei have shown that the general concept of shell structure is not as robust and universal as earlier thought, but can exhibit significant changes as a function of neutron excess. New magic numbers appear and some other conventional ones disappear mainly because of a different ordering of the single-particle orbitals. In the present contribution, recent experimental studies of neutron-rich Cu isotopes, performed at RIKEN using β decay and one-proton knockout reactions, will be discussed. Neutron-rich nuclei near ⁷⁸Ni were populated through in-flight fission of ²³⁸U on thick ⁹Be targets in both experiments. In the β-decay study, ^75,77Ni nuclei were implanted into the WAS3ABi silicon array, while γ rays from excited states in ^75,77Cu emitted after β decay of the implanted ions were detected with the EURICA Ge detector array that was surrounding the active stopper. In a second experiment within the SEASTAR campaign at RIKEN, the same ^75,77Cu nuclei were produced in (p,2p) knockout reactions from ^76,78Zn beam particles at around 250 MeV/nucleon impinging onto the MINOS liquid hydrogen target. In the latter experiment the DALI2 NaI array was used to detect de-excitation γ rays measured in coincidence with Cu nuclei identified in the Zero Degree Spectrometer. Both studies are complimentary and greatly contribute to our understanding on the nuclear structure in the ⁷⁸Ni region.