Louis Olivier
Published: 2017
Total Pages: 0
Get eBook
The nuclear shell structure is evolving when going into more and more exotic regions of the chart of isotopes and consequently, the conventional magic numbers (8, 20, 28, 50, 82, 126) may disappear far from stability, while some new magic numbers can appear. The 78Ni nucleus, with its 28 protons and 50 neutrons, is one of the most exotic supposedly doubly-magic nuclei, making it of great interest. The evolution of the Z = 28 gap towards N = 50 can be studied by probing the single-particle character of the states in the copper isotopic chain, having one proton more than nickel. This work focuses on Cu, at N = 50.In the aim of performing the first in-beam gamma-ray spectroscopy of nuclei in the close vicinity of 78Ni, an experiment was carried out at the Radioactive Isotope Beam Factory of RIKEN, in Japan. The 79Cu nucleus was produced through the (p,2p) knockout reaction from a 80Zn beam sent on the MINOS device, a liquid-hydrogen target coupled to a TPC used for proton tracking. The subsequent gamma-decay was detected in-beam with the DALI2 scintillator array. The BigRIPS and ZeroDegree spectrometers allowed an unambiguous identification of the incoming and outgoing nuclei, respectively.An analysis procedure based on gamma-gamma coincidences permitted to build the first level scheme of 79Cu, with levels up to 4.6 MeV, and the results were compared to Monte-Carlo shell-model calculations for interpretation. The conclusions show that the 79Cu nucleus is well described in terms of a valence proton outside a closed 78Ni core, implying the magic character of the latter.