Measurement of the Production Cross Sections for Isotopes of Transfermium Elements in Complete Fusion Reactions with the Subsequent Evaporation of a Proton and Neutrons

International audience; Experiments aimed at synthesizing and investigating the features of radioactive decay of isotopes of superheavy elements (Z ≥ 110) have been conducted in the Flerov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research. Complete fusion reactions of an accelerated beam of$^{48}$Ca ions with transactinide targets with the subsequent evaporation of several neutrons from excited compound nucleus are typically used in these experiments. “Exotic” reaction channels with the evaporation of protons and several neutrons may be used to produce more neutron-rich isotopes of superheavy elements. The production cross sections were measured in experiments at the SHELS separator for Db and Rf isotopes produced in xn and pxn channels of the$^{50}$Ti +$^{209}$Bi →$^{259}$Db* reaction. The ratio of cross sections σ(xn)/σ(pxn) was on the order of 100.