Measurement of the beta -Decay Branch in sup 180 Lu to Sup(180M)Hf for Investigation of the R-Process Nucleosynthesis of Sup(180M)Ta

摘要

The beta -decay branch of sup 180 Lu to sup(180m)Hf is measured by an integral method tracing the amount of sup(180m)Hf daughter activity, to be 0.46 (15)%. Samples of sup 180 Lu are prepared by on-line mass separation of sup 136 Xe-on-tungsten transfer reaction products. The amount of isobaric sup(180m)Hf in the samples is strongly suppressed by the employed separator ion source; its directly produced fraction is derived from comparison with sup(177m)Hf activity. The properties of lutetium and hafnium release from the ion source are separately determined. With this measurement r-process nucleosynthesis is estimated to account for at most 22% of the solar sup(180m)Ta abundance. (ERA citation 10:001482)