Nuclear structure of 153Pm studied with the (t,α) reaction

The 154SM(t,α) 153Pm reaction has been studied using a 17 MeV beam of polarized tritons from the tandem Van der Graaff accelerator at the Los Alamos Scientific Laboratory. The alpha spectra were recorded using a quadrupole-dipole-dipole-dipole magnetic spectrometer with a position-sensitive helical-cathode detector on the focal plane. Spectra were obtained to excitation energies > 2 MeV with a resolution of approx. 17 keV. It was possible to assign spins and parities to many of the levels by comparing the measured angular distributions of cross sections and analyzing powers with distorted-wave Born approximation predictions. The results are interpreted in terms of the Nilsson model with pairing and Coriolis mixing effects included. The 5/2-[532], 5/2+[413], 3/2+[411], and 1/2+[420] bands have been observed, as well as the 3/2-[541] and 3/2+[422] orbitals, which appear to be strongly Coriolis mixed with the 1/2-[550] and 1/2+[431] states, respectively. The results of these experiments confirm some of the assignments from a recent (d,3He) study and show that others were incorrect. Spectroscopic factors for the strongest transitions are in good agreement with expectations based on the model. The ground state Q value for the 154Sm(t,α)153Pm reaction was measured to be 10.748 +- 0.020 MeV