Abstract
Background: has rarely been studied as a projectile in fusion-evaporation reactions. The synthesis of new superheavy elements with will require projectiles with , and could potentially be used for this purpose.
Purpose: Cross sections were measured for the and exit channels in the reactions of with lanthanide targets for comparison to previous measurements of reacting with similar targets. These data provide insight on the survival of spherical, shell-stabilized nuclei against fission, and could have implications for the discovery of new superheavy elements.
Methods: Beams of were delivered from the K500 superconducting cyclotron at Texas A&M University with an energy of . Products were purified using the Momentum Achromat Recoil Spectrometer, and excitation functions were measured for reactions of , , and at five or more energies each. Evaporation residues were identified by their characteristic -decay energies. Experimental data were compared to a simple theoretical model to study each step in the fusion-evaporation process.
Results: The maximum measured cross sections for the reactions , , and are , , , , , and , respectively. Proton emission competes effectively with neutron emission from the excited compound nucleus in most cases. The , and products were also observed in the reaction.
Conclusions: Excitation functions were reported for -induced reactions on lanthanide targets for the first time, and these cross sections are much smaller than for -induced reactions on the same targets. The relative neutron-deficiency of the compound nuclei leads to significantly increased fissility and large reductions in the survival probability. Little evidence for improved production cross sections due to shell-stabilization was observed.
- Received 21 May 2015
- Revised 11 August 2015
DOI:https://doi.org/10.1103/PhysRevC.92.034613
©2015 American Physical Society