High-spin spectroscopy and shell-model interpretation of the N < 126 radium isotopes $^{212}$Ra and $^{213}$Ra

The level structures of Ra-212 and Ra-213 have been established via time-correlated gamma-ray spectroscopy following the Pb-204(C-12,4n)Ra-212 and Pb-204(C-13,4n)Ra-213 reactions. In Ra-212, levels up to similar to 6.2MeV were identified and firm spin-parity assignments were achieved to a J(pi) = 19(+) isomer with a mean life of 31(3) ns. For Ra-213 the corresponding values were similar to 4.5 MeV in excitation energy and J(pi) = 33/2(+). Two isomeric states with J(pi) = 23/2(+), tau = 27(3) ns and J(pi) = 33/2(+), tau = 50(3) ns were discovered in Ra-213. The experimental data were compared with semiempirical shell-model calculations, which allowed dominant configurations to be assigned to most of the observed levels.