Alpha-decay studies of the francium isotopes 198Fr and 199Fr nuclei
Uusitalo, J., Sarén, J., Juutinen, S., Leino, M., Eeckhaudt, S., Grahn, T., . . . Venhart, M. (2013). Alpha-decay studies of the francium isotopes 198Fr and 199Fr nuclei. Physical Review C, 87 (6), 064304. doi:10.1103/PhysRevC.87.064304
Published in
Physical Review CAuthors
Date
2013Discipline
FysiikkaCopyright
© 2013 American Physical Society. Published in this repository with the kind permission of the publisher.
Very neutron deficient francium isotopes have been produced in fusion evaporation reactions using 60Ni ions
on 141Pr 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 α-particle activities, with Eα = 7613(15) keV and T1/2 = (15+12
−5 ) ms and
Eα = 7684(15) keV and T1/2 = (16+13
−5 ) ms were identified in the new isotope 198Fr. In addition, the half-life and
α-particle energy of 199Fr were measured with improved precision. The measured decay properties deduced for 199Fr and 198Fr suggest that there is an onset of ground-state deformation at N = 112 in the Fr isotopes.