Isotope shifts have been measured for the odd-A polonium isotopes Po and changes in the nuclear mean square charge radii 〈r〉 have been deduced. The measurements were performed at CERN-ISOLDE using the in-source resonance-ionization spectroscopy technique. The combined analysis of these data and our recent results for even-A polonium isotopes indicates an onset of deformation already at Po, when going away from stability. This is significantly earlier than was suggested by previous theoretical and experimental studies of the polonium isotopes. Moreover and in contrast to the mercury isotopes, where a strong odd-even staggering of the charge radii of the ground states was observed by approaching the neutron mid-shell at N=104, no such effect is present in polonium down to Po. Consequently the charge radii of both isomeric and ground states of the odd-A polonium isotopes follow the same trend as the even-A isotopes.
|Journal||Physics Letters B : Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 26 Feb 2013|