Pauli blocking in the low-lying, low-spin states of Pr141

The low-lying, low-spin levels of Pr141 were investigated using (n,n'γ) techniques. Level energies, branching ratios, and tentative spin assignments for more than 100 states, linked by nearly 300 transitions, were obtained from two angular distributions (En=2.0 and 3.0 MeV) and an excitation function measurement (En=1.5-3.2 MeV). The application of the Doppler-shift attenuation method led to the determination of lifetimes. The obtained spectroscopic data provide insight into the wave functions of the states observed. A detailed analysis of the [21+d5/2] and [21+g7/2] multiplets provides the first quantitative evidence for Pauli blocking in a spherical odd-mass nucleus. The unpaired particle is used to probe the microscopic structure of the first 2+ state of the adjacent core nuclei Ce140 and Nd142.