A new nuclide ${}_{}{}^{263}{}_{}{}^{}\mathrm{Ha}$ was produced in the bombardment of a ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$ target with 93-MeV ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ ions. It was detected via spontaneous fission counting and was shown to have a half-life of about 0.5 min. This activity was also separated from the reaction products by automated rapid chemical separations using cation-exchange chromatography in 0.05M α-hydroxyisobutyric acid. After chemical separation, ${}_{}{}^{263}{}_{}{}^{}\mathrm{Ha}$ was found to decay by spontaneous fission (${57}_{\mathrm{-}15}^{+13\mathrm{}}$%) and by α emission (${\mathit{E}}_{\mathrm{\alpha }}$=8.35 MeV, 43%) with a half-life of ${27}_{\mathrm{-}7}^{+10\mathrm{}}$ s. The spontaneous fission fragment energy spectrum is compatible with an average total kinetic energy of about 200 MeV.

• Received 17 April 1991

DOI:https://doi.org/10.1103/PhysRevC.45.1064