Eleven new heaviest isotopes of elements Z=105 to Z=117 identified among the products of Bk249+Ca48 reactions

Abstract

The heaviest isotopes of elements Z=117 to Z=105, 294117, 293117, 290115, 289115, 286113, 285113, Rg282, Rg281, Mt278, Bh274, and Db270, were identified by means of the Dubna gas-filled recoil separator among the products of the Bk249 + Ca48 reaction. The details of the observed six decay chains, indicating the production and decay of isotopes 293117 and 294117, are presented and discussed. The decay energies and resulting half-lives of these new nuclei show a strong rise of stability with increasing neutron number, validating the concept of the island of enhanced stability for superheavy nuclei. © 2011 American Physical Society.