Erlangen 2022 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 9: Ion Storage Rings
MS 9.3: Vortrag
Donnerstag, 17. März 2022, 14:45–15:00, MS-H9
Measurement of the bound-state beta decay of bare 205-Thallium and its nuclear astrophysical implications — •Ragandeep Singh Sidhu, Rui-Jiu Chen, Yu. A. Litvinov, and and the E121 collaboration — GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany
We report on the first direct measurement of the bound-state beta decay [1] of 205Tl81+ ions, an exotic decay mode, in which an electron is directly created in one of the empty atomic orbitals instead of being emitted into the continuum. One of the most awaited and pioneering experiments was realized in the spring beamtime at GSI, Darmstadt in 2020, wherein the entire accelerator chain was employed. 205Tl81+ ions (with no electron) were produced with the projectile fragmentation of 206Pb primary beam on 9Be target, separated in the fragment separator (FRS), accumulated, cooled, and stored for different storage times (up to 10 hours) in the experimental storage ring (ESR). The experimentally measured half-life value [2] draws a 2.7σ [3] and 4.2σ [4] tension with the theoretically predicted values, which could influence our understanding of the abundance of
chemical elements in the early universe. In this contribution, the authors aim to present the s-process motivation and a preliminary value of the 205Tl81+ half-life.
[1] R. Daudel et al., J. Phys. Radium, 8, 238, 1947.
[2] Ragandeep Singh Sidhu, Ph.D. Thesis, Ruprecht-Karls-Universität, 2021.
[3] K. Takahashi et al., Phys. Rev. C, 36, 1522, 1987.
[4] S. Liu et al., Phys. Rev. C, 104, 024304, 2021.