Abstract
Irradiations of and targets with beams aimed at the synthesis of flerovium isotopes were performed at the Dubna Gas Filled Recoil Separator. A new spontaneously fissioning (SF) isotope was produced for the first time in the (250 MeV) and (245 MeV) reactions. The cross section of the reaction channel was about 20 times lower than predicted by theoretical models and about 50 times lower than the maximum fusion-evaporation cross section for the and channels measured in the reaction. In the experiment, performed at 245 MeV in order to maximize the -evaporation channel, three decay chains of were detected. The -decay energy of was measured for the first time and decay properties of its descendants , and were determined with higher accuracy. The assignment of SF events observed during the irradiation of the target with a 250 MeV beam to decay is presented and discussed. The cross sections at both energies are similar and exceed that observed in the reaction with the lighter isotope by a factor of 10. The decay properties of the synthesized nuclei and their production cross sections indicate a rapid decrease of stability of superheavy nuclei as the neutron number decreases from the predicted magic neutron number .
- Received 22 July 2015
DOI:https://doi.org/10.1103/PhysRevC.92.034609
©2015 American Physical Society