Systematic studies of β-decay half-lives of new neutron-rich lanthanide isotopes

Abstract

β-decay half-lives are one of the important quantities related to the stability of neutron-rich nuclei as well as to the astrophysical calculations involving the rapid neutron capture process (r-process). Although the nuclei studied up to the present do not directly affect the evaluation of the nuclidic abundances produced in the r-process, their experimental half-lives give a good opportunity to verify the validity of various theoretical calculations of β-decay half-lives. In the previous work, we determined β-decay half-lives of the isotopes 161Sm, 165Gd, and 166,167,168Tb [1,2] produced in the proton-induced fission of 238U, and it was found that the half-life values observed are in good agreement with those predicted from the gross theory. In this report, we present the newly determined half-life values of the further three isotopes 159Pm, 162Sm and 166Gd together with that of the re-measured 166Tb.