Investigation of the 243Am+48Ca reaction products previously observed in the experiments on elements 113, 115, and 117

Results from the production and decay properties of element 115 nuclei observed using the reaction Am-243 + Ca-48 at various beam energies between November 1, 2010, and February 26, 2012, at the Dubna Gas Filled Recoil Separator are presented. This long-running experiment with a total beam dose of 3.3 x 10(19) and carried out in the excitation energy range E* = 31-47 MeV of the (291)115 compound nucleus resulted in observation of three isotopes of element 115 with masses 287, 288, and 289. The 28 detected decay chains of (288)115 show that this isotope is produced with the maximum probability at E* = 34.0-38.3 MeV with a corresponding cross section of sigma(3n) = 8.5(-3.7)(+6.4) pb. The four events attributed to the isotope (289)115 that decays via a short alpha --> alpha --> SF chain could be detected only at the lowest excitation energy E* = 31-36 MeV, in accordance with what could be expected for the 2n-evaporation channel of the reaction. The decay characteristics of this nuclide were established earlier (2010) and more recently (2012) in the reaction Bk-249(Ca-48,4n)(293)117 and following alpha decay to (289)115. At the energy E* = 44.8 +/- 2.3 MeV we observed only a single long chain of the isotope (287)115. The decay properties of nuclei starting at (288)115 and (287)115 isotopes obtained in the present work reproduce in full the results of the first experiment of 2003 that reported the discovery of elements 115 and 113. The excitation functions of the production of the isotopes of element 115 and observation of the isotope (289)115 in cross-bombardment reactions with the targets of Am-243 and Bk-249 provide additional evidence of the identification of the nuclei of elements 115 and 113. The experiments were carried out using the Ca-48 beam of the U400 cyclotron of the Flerov Laboratory of Nuclear Reactions, JINR. DOI: 10.1103/PhysRevC.87.014302