Systematic study of the γ-ray strength function of samarium isotopes

An upbend in the low-energy region of the γ-ray strength function has been observed previously in ^151,153Sm isotopes. This enhancement of the γSF for energies below 2 MeV has profound implications on the neutron capture rates important for modeling the astrophysical r-process. A series of theoretical and experimental studies have been focused to understand the origin of this phenomenon. In this talk, the results of the measurements of γSF for ^{147,149,151,153}Sm isotopes are discussed. The nuclei of interest were populated via (p,d) reactions on pure ^{148,150,152,154}Sm targets and the reaction products were recorded by the Hyperion γ-ray array. The observed systematic highlights the interplay between scissors mode and the upbend. A Shell-model comparison shows reasonable agreement with the experimental γSFs and confirms the correspondence between the upbend and scissors mode