GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt
   



Contribution 'Tours Symposium on Nuclear Physics III', Tours, France, Sept. 2nd - 5th, 1997
AIP Conference Proceedings 425, Woodbury, New York (1998), 3

GSI Experiments on the Synthesis of superheavy elements

[Hess97a]
F.P. Heßberger(1), S. Hofmann(1), V. Ninov(1) , P. Armbruster(1), H. Folger(1), A. Lavrentev(2), M.E. Leino(3), G. Münzenberg(1), A.G. Popeko(2), S. Saro(4), Ch. Stodel(1), A.V. Yeremin(2)
(1) Gesellschaft für Schwerionenforschung, D-64220 Darmstadt Germany
(2) Flerov Laboratory of Nuclear Reactions, JINR, 141980 Dubna, Russia
(3) Dept. of Physics, University of Jyv&aunl;skylä, FIN-40351 Jyväskylä, Finland
(4) Dept. of Physics, Comenius University, SK-84215 Bratislava, Slowakia


Abstract:

Evaporation residue production was investigated at SHIP in cold fusion reactions of Pb- and Bi- target nuclei with projectiles of elements between Ti (Z=22) and Zn (Z=34) leading to compound nuclei Z_CN = 104 - 116. The isotopes 269-110, 271-110, 271-111 and 277-112 of the elements Z = 110, Z = 111 and Z = 112 were unambiguously identified for the first time in bombardments of Pb-206, Bi-209 with Ni-62,64 and Zn-64. Excitation functions for Ti-50 + Pb-208 and Fe-58 + Pb-208 were measured with high precision; three new spontaneous fission (sf) activities 253-104, 254-104, 258-106 were identified. A small alpha - branch of the even - even nucleus 256-104 ( b(alpha) = 0.003 ) was confirmed, allowing to estimate mass excesses (Delta)mc**2 for N-Z = 48 nuclei up to Hs-264 (Z=108). An analysis of the alpha - decay chains observed in a bombardment of Bi-209 with Fe-58 - projectiles showed evidence for an isomeric state in Mt-266 (Z=109). We further report on an attempt to produce element 116 and a second isotope of element 112 by the reactions Se-82 + Pb-208 and Zn-68 + Pb-208, respectively.


Letzte Änderung: 28. Feb. 2006