Abstract
Very neutron deficient francium isotopes have been produced in fusion evaporation reactions using Ni ions on Pr targets. The gas-filled recoil separator RITU was employed to collect the fusion products and to separate them from the scattered beam. The activities were implanted into a position sensitive silicon detector after passing through a gas-counter system. The isotopes were identified using spatial and time correlations between the implants and the decays. Two -particle activities, with keV and () ms and keV and () ms were identified in the new isotope Fr. In addition, the half-life and -particle energy of Fr were measured with improved precision. The measured decay properties deduced for Fr and Fr suggest that there is an onset of ground-state deformation at in the Fr isotopes.
- Received 30 November 2012
DOI:https://doi.org/10.1103/PhysRevC.87.064304
©2013 American Physical Society