The new element 111

Abstract

The new element 111 was produced and unambiguously identified in an experiment at SHIP, GSI Darmstadt. Three nuclei of the isotope272111 were observed in irradiations of209Bi targets with64Ni projectiles of 318 MeV and 320 MeV energy. The cross-sections are (1.7-1.4+3.3) pb and (3.5-2.3+4.6) pb, respectively. The nuclei decay by a emission into the new and so far the heaviest isotopes of the elements 109 and 107 with mass numbers A=268 and A=264. The α-decay chains were followed down to the known nuclei260105 and256Lr. © 1995 Springer-Verlag.