Low-Lying Collective States ofSm152andSm154

Abstract

The excited states up to 2 MeV in ${\mathrm{Sm}}^{152}$ and ${\mathrm{Sm}}^{154}$ have been studied by magnetic analysis of the inelastic protons from thin targets bombarded by a 12-MeV proton beam from the Florida State University tandem Van de Graaff accelerator. The results are compared with previous studies and with the predictions of collective nuclear models. The ground-state band levels up to spin 6 are excited in these experiments. The 2+, 3+, and 4+ states in the gamma vibrational band, the 0+ and 2+ states in the beta vibrational band, and the 1-, 3-, and 5- states in the octupole band have been observed in ${\mathrm{Sm}}^{152}$. In ${\mathrm{Sm}}^{154}$ the gamma band head is observed at 1443 keV and the octupole band head is observed at 927 keV. Additional levels in these bands and the beta band are suggested. Several other levels are observed above 1100 keV in these nuclei.