Study of the neutron deficient Pb182-190 isotopes by simultaneous atomic- and nuclear-spectroscopy
Seliverstov, M × Andreyev, Andrei Barre, N De Witte, Hilde Fedorov, D Fedoseyev, V Franchoo, S Genevey, J Huber, G Huyse, Marc Koster, U Kunz, P Lesher, S Marsh, B Roussiere, B Sauvage, J Van Duppen, Piet Volkov, Yu #
Mean-square charge radii and magnetic moments have been measured for the neutron deficient lead isotopes, Pb182-190. The measurement was performed at the ISOLDE online mass separator, using the in-source resonance ionization spectroscopy technique. The wavelength of the first excitation step for the resonance ionization laser ion source (RILIS) was scanned over the resonance(s) whilst the alpha- and gamma-ray spectra from the decay of the Pb isotopes were recorded as a function of the wavelength. The isotope shift and, in the case of odd-A isotopes, the hyperfine splitting were deduced. The rms-charge radii of the very neutron deficient Pb isotopes follow the smooth trend of the heavier isotopes. This finding indicates a spherical shape for the lead ground states at the neutron mid-shell (N = 104), where the excitation energy of the oblate 0(+) state in the even isotopes reaches its minimum.