Spontaneous-fission decay properties and production cross-sections for the neutron-deficient nobelium isotopes formed in the reactionsA.V. Belozerov1, M.L. Chelnokov1, V.I. Chepigin1, T.P. Drobina1, V.A. Gorshkov1, A.P. Kabachenko1, O.N. Malyshev1, I.M. Merkin1, Yu.Ts. Oganessian1, A.G. Popeko1, R.N. Sagaidak1, A.I. Svirikhin1, A.V. Yeremin1, G. Berek2, I. Brida2 and S. Sáro2
1 Flerov Laboratory of Nuclear Reactions, JINR, 141980 Dubna, Russia
2 Comenius University, SK-84215 Bratislava, Slovakia
(Received: 26 July 2002 / Revised version: 16 October 2002 / Published online: 18 March 2003)
Heavy-ion fusion reactions 48Ca + 204Pb and 44Ca + 208Pb leading to the same compound nucleus 252No * were run in attempts to produce new neutron-deficient spontaneous-fission isotopes of 249,250No using the electrostatic separator VASSILISSA. Production cross-sections for the spontaneous-fission activities with the half-lives 5.6 and 54 s observed in these reactions are compared with the measured ones for the well-known isotopes of 251 - 255No formed in the heavy-ion fusion reactions 48Ca + 206Pb and 48Ca + 208Pb. The obtained excitation functions for the reaction products formed after the evaporation of 1-4 neutrons from the corresponding compound No nuclei have been compared with similar data obtained earlier and results of statistical model calculations.
21.10.Dr - Binding energies and masses.
23.60.+e - Alpha decay.
25.70.-z - Low and intermediate energy heavy-ion reactions.
25.85.Ca - Spontaneous fission.
© Società Italiana di Fisica, Springer-Verlag 2003