Low-spin structure of the N=82 nucleus Cs 137

Excited states in Cs137 have been studied by using the near-barrier, single-proton transfer reaction B10(Xe136,Be9γ)Cs137 in inverse kinematics and performing particle-γ and particle-γγ coincidence measurements. The low-spin level scheme of Cs137 has been augmented: (i) The expected set of single-proton, seniority υ=1 states has been delineated in its entirety; (ii) Another member of the υ=3 proton 0g7/2 multiplet, a low-lying 9/2+ level, has been identified and this set of states now approaches completion; (iii) A second 9/2+ and a candidate 13/2+ level have been observed. The results are discussed in the framework of shell-model calculations in the proton 2s1d0g0h shell.