The structure of ${}_{}{}^{215}{}_{}{}^{}\mathrm{Fr}$ has been studied via the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ ${(}^{11}$B, 4nγ${)}^{215}$Fr reaction at beam energies from 45 to 66 MeV. In-beam γ-ray spectroscopy techniques, including γ-ray excitation function, x-ray-γ coincidence, γ-γ coincidence, γ-ray angular distribution, and γ-ray linear polarization measurements were used to construct a level scheme up to a spin value J=(41/2) at an excitation energy of 3405 keV. Definite parity assignments were made up to the ${\mathrm{}(39/2)\mathrm{}}^{\mathrm{-}}$ state. The structure of this nucleus is compared with that observed in the other N=128 isotopes and predictions of shell model calculations.

• Received 30 January 1985

DOI:https://doi.org/10.1103/PhysRevC.32.136