test_moissonnage_selune
type: Agent

Evolution of the shell structure in medium-mass nuclei : search for the 2d5/2 neutron orbital in 69Ni
type: Dataset
contact point: Organization
  fn: CCSD
keyword: ilot-dinversion-n40
keyword: noyaux-riches-en-neutrons
keyword: theses
keyword: nuclear-structure
keyword: reaction-de-transfert
keyword: infoeu-reposemanticsdoctoralthesis
keyword: structure-nucleaire
keyword: physnexpphysics-physicsnuclear-experiment-nucl-ex
keyword: neutron-rich-nuclei
keyword: cinematique-inverse
keyword: calculs-de-modele-en-couches
keyword: transfer-reaction
keyword: inverse-kinematics
keyword: shell-model-calculations
keyword: island-of-inversion-n40
landing page: https://theses.hal.science/tel-00759572
description: The harmonic oscillator shell closure at N=40 in 68Ni is weak and loses its strength when removing (or adding) pair of protons. Calculations performed in this mass region predict a new island of inversion at N=40 similar to the one at N=20. Using a large valence space, the neutron orbital 2d5/2 is shown to be a crucial ingredient for the interpretation of the nuclear structure at N≈40. The neutron 1g9/2-2d5/2 energy difference has been determined in 69Ni using the d(68Ni,p) transfer reaction in inverse kinematics. The experiment performed at GANIL used a 68Ni beam at 25.14 MeV/u seperated by the LISE3 spectrometer was impinging a CD2 target of 2.6 mg/cm2 thickness. The experimental setup consisted of CATS/MUST2-S1/EXOGAM detectors coupled to an ionization chamber and a plastic scintillator. The angular momenta and spectroscopic factors of the ground state (Jπ = 9/2+) and a doublet of states ( Jπ = 5/2+) around 2.48 MeV corresponding to the population of the 1g9/2 and the 2d5/2 orbitals, were obtained from the comparison between the experimental cross-sections as a function of the proton detection angle and ADWA calculations. The spins of the observed states were assigned by comparaison to large scale Shell-Model calculations. The position of the 2d5/2 orbital in 69Ni has been established for the first time. Our measurements support the hypothesis of a low-lying 2d5/2 orbital (≈2,5 MeV) with respect to the 1g9/2 neutron orbital and thus its major role in the structure of the nuclei around N=40.
identifier: NNT: 2012STRAE011
issued: 2026-06-03T00:44:03.540582
language: en
modified: 2026-06-03T00:44:03.540588

Evolution of the shell structure in medium-mass nuclei : search for the 2d5/2 neutron orbital in 69Ni
type: Distribution
access URL: https://theses.hal.science/tel-00759572
format: HTML
issued: 2026-06-03T00:44:03.666441
modified: 2026-06-03T00:44:03.500986