Abstract

Neutron-rich lanthanides were produced via in-flight fission of a 238U primary beam at the RIBF, RIKEN Nishina Center to measure half-lives (T1/2) and beta-delayed neutron emission probabilities (Pn) in order to constrain r-process abundance calculations. 159–166Pm, 161–168Sm, 165–170Eu, and 167–172Gd ions were implanted in the Advanced Implantation Detector Array (AIDA), and β-delayed neutrons and γ-rays were detected by the surrounding detector array (BRIKEN). For the validation of T1/2 values derived from implantation–β (i–β) time correlations, γ-spectroscopic methods were used as well. The experimental results of the β-delayed γ-spectroscopy of 162Pm are presented here as an example. A half-life value from γ-decay curves was derived with a comparable uncertainty to the result from the i–β method, and a mean value well within the 1σ range.