High-precision mass measurements of nickel, copper, and gallium isotopes and the purported shell closure at N=40

Abstract

High-precision mass measurements of more than thirty neutron-rich nuclides around the Z=28 closed proton shell were performed with the triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN to address the question of a possible neutron shell closure at N=40. The results, for 57,60,64-69Ni (Z=28), 65-74,76Cu (Z=29), and 63-65,68-78Ga (Z=31), have a relative uncertainty of the order of 10^8. In particular, the masses of 72-74,76Cu have been measured for the first time. We analyse the resulting mass surface for signs of magicity, comparing the behavior of N=40 to that of known magic numbers and to mid-shell behavior. Contrary to nuclear spectroscopy studies, no indications of a shell or sub-shell closure are found for N=40.

14 figures

References in corpus (1)

• Nuclear Magnetic Moment of the 57Cu Ground State

Cited by in corpus (15)

• ${}^{78}$Ni revealed as a doubly magic stronghold against nuclear deformation
• Laser Spectroscopy for the Study of Exotic Nuclei
• Evolution of the N=50 shell gap energy towards ${}^{78}$Ni
• Nuclear spins, magnetic moments and quadrupole moments of Cu isotopes from N = 28 to N = 46: probes for core polarization effects
• Collectivity-induced quenching of signatures for shell closures
• Fragmentation cross-sections and binding energies of neutron-rich nuclei
• Coulomb excitation of ${}^{68}$Ni at safe energies
• Atomic mass measurements of short-lived nuclides around the doubly-magic 208Pb
• Penning trap mass measurements on (99-109)$Cd with ISOLTRAP and implications on the rp process
• Lifetime measurements in ${}^{63}$Co and ${}^{65}$Co
• Nuclear Moments of Germanium Isotopes around $N$ = 40
• Precision Mass Measurements of Neutron-Rich Co Isotopes Beyond N=40
• beta-decay study of Cu-77
• Nuclear charge radii of germanium isotopes around $N$ = 40
• The 76Cu conundrum remains unsolved