Nuclear Data Sheets for A = 151

Abstract

Nuclear spectroscopic information for known nuclides of mass number 151 (Cs,Ba,La,Ce,Pr,Nd,Pm,Sm,Eu, Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu) with Z = 55 to 71 and N = 96 to 80 have been evaluated and presented together with adopted energies and Jπ of levels in these nuclei. No excited state data are yet available for 151Cs, 151Ba and 151La; only the isotopic identification has been reported, without information about their half-lives or decay modes. The 151Hf nuclide has not yet been identified. The radioactive decays of 151Ce, 151Ho (35.2-s and 47.2-s activities), 151Er (23.5-s and 0.58-s activities), 151Yb (two activities of about the same half-life) are not well established. For the decay of 151Lu, only the half-life is known. Superdeformed structures are well established in 151Dy and 151Tb with a total of five SD bands in 151Dy and ten SD bands in 151Tb. In 151Gd, six SD bands have been tentatively assigned. In 151Tb, yrast SD-1 band has now (2008Ro23) been linked to normal-deformed structures through two well-defined high-energy γ transitions and possibly four other tentative γ rays. This evaluation represents a revision of earlier (1997Si03,1988Si15,1976Ha35) evaluations of A = 151.