Decay properties and lifetimes of states in ¹⁴⁴Sm from (n, n'γ) reaction studies

An extensive investigation of ¹⁴⁴Sm has been carried out with the (n, n'γ) reaction. Gamma-ray excitation function and angular-distribution measurements were performed at neutron energies up to 4.3 MeV. Many new levels have been established and characterized, and the assignments of several previously known states have been clarified. Level lifetimes were measured following the inelastic neutron-scattering reaction by observing the Doppler shifts of de-exciting γ-rays, and reduced transition rates have been inferred. Recent shell-model calculations were found to describe the ¹⁴⁴Sm level scheme very well up to 3.2 MeV. A large number of relatively fast E1 transitions were observed.