Measurement of the?-decay branch in180Lu to180m Hf for Investigation of the r-process nucleosynthesis of180m Ta

Abstract

The/?-decay branch of aS~ to ls~ is measured by an integral method tracing the amount of lS~ daughter activity, to be 0.46 (15)%. Samples of lS~ are wepared by on-line mass separation of 136Xe-on-tungsten transfer reaction products. The amount of isobaric ~8~ in the samples is strongly suppressed by the employed separator ion source; its directly produced fraction is derived from comparison with 177mHf 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 18~ abundance.

Isomer-to-isomer beta decay ofHfm180and the nucleosynthesis ofKellogg1, Norman2 1992Phys. Rev. C18062View full textAdd to dashboardCite

“…who found f = 0.46+0. 15% [31]. Attempts to reconcile this difference by searching for a possible high-spin isomer of Lu have been fruitless to date [32,33].…”

The decay of the new isotope180Yb and the search for ther-Process path to180mTa

“…It would require a weak fl-branch 18~ ts~ which was only derived from indirect methods, giving the contradictory results off,. = 0.46 (15)% [3] and 0.005(18)% [4]. In view of this discrepancy, we attempted a direct observation by identifying fldelayed y-lines feeding the U = 8 --i s o m e r in 18~ We also searched for a high-spin isomer in 18~ which could be responsible for the population of 18~ as well and play a key role [3,4] in the stellar synthesis of 18~…”

Evidence for a high-spinβ-decaying isomer inLu177

“…The application of the two-component-decay formula is based on the premise of a constant lutetium production and prompt release from the ion source. In previous work, the release properties of lutetium from a thermal ion source have been measured [43] and affected the decay constants in expression (3.1). Due to the uncertainties in the original premise for this analysis due to the release properties of the ion source, a second, independent method to determine the half-life of the proposed higher-lying decay was used.…”