Search for new isotopes of element 112 by irradiation of 238U with 48Ca
Yu.Ts. Oganessian1 - A.V. Yeremin1 - G.G. Gulbekian1 - S.L. Bogomolov1 - V.I. Chepigin1 - B.N. Gikal1 - V.A. Gorshkov1 - M.G. Itkis1 - A.P. Kabachenko1 - V.B. Kutner1 - A.Yu. Lavrentev1 - O.N. Malyshev1 - A.G. Popeko1 - J. Rohác1 - R.N. Sagaidak1 - S. Hofmann2 - G. Münzenberg2 - M. Veselsky3 - S. Saro4 - N. Iwasa5 - K. Morita5
1 Flerov Laboratory of Nuclear Reactions, JINR, 141980 Dubna, Russia
2 Gesellschaft für Schwerionenforschung, D-64220 Darmstadt, Germany
3 Institute of Physics, Dubravska 9, SK-84228 Bratislava, Slovakia
4 Department of Physics, Comenius University, SK-84215 Bratislava, Slovakia
5 Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-01, Japan
Received: 12 October 1998 / Revised version: 12 January 1999 Communicated by D. Guerreau
Abstract
The reaction 48Ca+238U was investigated at the recoil
separator VASSILISSA at the Flerov Laboratory of Nuclear Reactions,
JINR Dubna, in attempts to synthesize new isotopes of element 112.
The experiments were performed at two beam energies resulting in
excitation energies of the compound nucleus of 33 and 39 MeV. The
collected beam dose was 3.5
1018 and 2.21018,
respectively. Two spontaneous fission events were observed at the
lower beam energy, which tentatively were assigned to the new neutron
rich isotope 283112 produced in the reaction
238U(48Ca,3n)283112. The measured cross-section is
(5.0 +6.3-3.2) pb and the half-life is (81 +147- 32) s.
No event was observed at the higher beam energy resulting in the
upper cross-section limit of 7.3 pb.
PACS
21.10.Dr Binding energies, masses and excitation energy -
23.60.+e 
-decay -
25.70.-z Heavy ion induced reactions and scattering -
25.85.Ca Spontaneous fission -
27.90.+b 220
A
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