Half-Life of the New IsotopeNa32; Observation ofNa33and Other New Isotopes Produced in the Reaction of High-Energy Protons on U

With an improved on-line mass spectrometer we have discovered, by means of the reaction of 24-GeV protons on uranium, the very neutron-rich isotope ${}_{}{}^{32}{}_{}{}^{}\mathrm{Na}$ and measured its half-life. We have also produced in the same reaction the new isotopes ${}_{}{}^{33}{}_{}{}^{}\mathrm{Na}$, ${}_{}{}^{48-50}{}_{}{}^{}\mathrm{K}$, and ${}_{}{}^{227,228}{}_{}{}^{}\mathrm{Fr}$. There is evidence for shell effects in the cross sections of the new sodium isotopes.