Gamma-ray transitions in 159Tb following the (n,n') reaction

Energy levels of ¹⁵⁹Tb have been studied from the γ-ray spectrum produced by the ¹⁵⁹Tb(n,n′γ) reaction using a Ge(Li) detector. The spectrum shows peaks at 317, 331, 395, 440, and 520 keV which do not fit into the existing level scheme of ¹⁵⁹Tb. The possibility that the γ-ray transitions found at 912, 947, and 976keV might belong to a 1/2⁺[411] rotational band is discussed. A γ ray at 248 keV is interpreted as a transition originating in the recently found 386-keV level. The weak transition from the 429-keV level to the ground state has been detected. Some doublets in the γ spectrum are discussed.