Abstract
A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the and fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the target partially decayed into , which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the and reactions, respectively, at a midtarget beam energy of MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical predictions on the fission-barrier heights of superheavy nuclei in the region of the island of stability.
- Received 10 September 2020
- Accepted 7 October 2020
DOI:https://doi.org/10.1103/PhysRevC.102.064602
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