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New algorithms to operate with new analog spectrometer of the DGFRS-2 installed at DC-280 cyclotron setup are presented. The main goal of application of these algorithms is to search an optimal time correlation recoil-alpha parameter directly during the acquisition C++ code execution. A new real-time flexible algorithm is presented in addition to the conventional ER-α one which is in use for a few years at the DGFRS-1 setup installed at the U-400 FLNR cyclotron. Note that the spectrometer operates together with the 48 × 128 strip DSSD (Double Side Strip Detector; 48 × 226 mm2) detector and low pressure pentane-filled gaseous detector (1.2 Torr; 80 × 230 mm2) are presented schematically. First beam test results in 48Ca induced nuclear reactions are presented too. [ABSTRACT FROM AUTHOR]

Abstract: Three approaches to the measurement of a rare α decaying products produced in heavy-ion induced nuclear reactions are described. One is based on a chemical extraction and following deposition of the nuclides under investigation onto the surface of the detector, whereas the second one is associated with long–lived products implanted into silicon detectors by using the electromagnetic separation technique. The third approach relates with an application of real-time mode detection of correlated energy–time–position recoil-α sequences from 48Ca induced nuclear reactions with actinide targets, like 242, 244Pu, 245, 248Cm, 239Am and 249Cf. Namely with this technique, it has became possible to provide a radical suppression of backgrounds in the full fusion (3–5n) reactions aimed to the synthesis of super heavy elements with Z=113–116. [Copyright &y& Elsevier]

We have studied the dependence of the production cross-sections of the isotopes 282, 283112 and 286-288114 on the excitation energy of the compound nuclei 286112 and 290114. The maximum cross-sections of the xn-evaporation channels for the reaction 238 U(48 Ca, xn)286-x112 were measured to be: σ3n = 2.5+1.8-1.1pb and σ4n = 0.6+1.6-0.5pb; for the reaction 242 Pu(48 Ca, xn)290-x114: σ2n ∼ 0.5pb, σ3n = 3.6+3.4-1.7pb and σ4n = 4.5+3.6-1.9pb. In the reaction 233 U(48 Ca, 2-4 n)277-279112 we measured an upper cross-section limit of σxn≤0.6pb. An increase of σER in the reactions of actinide targets with 48Ca can be due to the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell N = 184. The observed nuclear decay properties of the nuclides with Z = 104-118 are compared with theoretical nuclear mass calculations and the systematic trends of α-decay properties. As a whole, they give a consistent pattern of decay of the 18 even- Z neutron-rich nuclides with Z = 104-118 and N = 163-177. [ABSTRACT FROM AUTHOR]

A PC-based algorithm (coded in C++) to extract in real-time the correlated recoil-alpha sequences in heavy-ion induced nuclear reactions has been designed and applied in various experiments aimed at the synthesis of superheavy elements. The algorithm operates together with the data acquisition system of the Dubna Gas-Filled Recoil Separator (GFRS). The GFRS detector module design is also presented. [Copyright &y& Elsevier]

Results from the production and decay properties of element 115 nuclei observed using the reaction 243 Am + 48Caat 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 × 1019 and carried out in the excitation energy range E* = 31-47 MeV of the 291115 compound nucleus resulted in observation of three isotopes of element 115 with masses 287, 288, and 289. The 28 detected decay chains of 288115 show that this isotope is produced with the maximum probability at E* = 34.0-38.3 MeV with a corresponding cross section of σ3n = 8.5-3.7+6.4Pb- The four events attributed to the isotope 289115 that decays via a short ɑ --> ɑ -» 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 249Bk(48Ca,4n)239117 and following a decay to 289115. At the energy E* = 44.8 ± 2.3 MeV we observed only a single long chain of the isotope 287115. The decay properties of nuclei starting at 288115 and 287115 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 289115 in cross-bombardment reactions with the targets of 243Am and 249Bk provide additional evidence of the identification of the nuclei of elements 115 and 113. The experiments were carried out using the 48Ca beam of the U400 cyclotron of the Flerov Laboratory of Nuclear Reactions, JINR. [ABSTRACT FROM AUTHOR]