The results of experiments designed to synthesize element 115 isotopes in the reaction are presented. With a beam dose of projectiles, we observed three similar decay chains consisting of five consecutive decays, all detected in time intervals of about and terminated at a later time by a spontaneous fission with a high-energy release (total kinetic energy ). At a higher bombarding energy of , with an equal beam dose, we registered a different decay chain of four consecutive decays detected in a time interval of about , also terminated by spontaneous fission. The decay energies and half-lives for nine new -decaying nuclei are given. The decay properties of these synthesized nuclei are consistent with consecutive decays originating from the parent isotopes of the new element 115, and , produced in the - and -evaporation channels with cross sections of about and , respectively. The radioactive properties of the new odd- nuclei are compared with the predictions of the macroscopic-microscopic theory. The experiments were carried out at the U400 cyclotron with the recoil separator DGFRS at FLNR, JINR.
- Received 8 September 2003
- Published 2 February 2004
- Publisher error corrected 3 February 2004
© 2004 The American Physical Society