DOI: 10.1140/epja/i2002-10109-6
Spontaneous-fission decay properties and production cross-sections
for the neutron-deficient nobelium isotopes formed in the
reactions
A.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
eremin@sunvas.jinr.ru
(Received: 26 July 2002 / Revised version: 16 October 2002 / Published online: 18 March 2003)
Abstract
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