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Open Access Publications from the University of California

Low-lying states in Ra 219 and Rn 215: Sampling microsecond α -decaying nuclei

  • Author(s): Såmark-Roth, A
  • Sarmiento, LG
  • Rudolph, D
  • Ljungberg, J
  • Carlsson, BG
  • Fahlander, C
  • Forsberg, U
  • Golubev, P
  • Ragnarsson, I
  • Ackermann, D
  • Andersson, LL
  • Block, M
  • Brand, H
  • Cox, DM
  • Di Nitto, A
  • Düllmann, CE
  • Eberhardt, K
  • Even, J
  • Gates, JM
  • Gerl, J
  • Gregorich, KE
  • Gross, CJ
  • Herzberg, RD
  • Heßberger, FP
  • Jäger, E
  • Khuyagbaatar, J
  • Kindler, B
  • Kojouharov, I
  • Kratz, JV
  • Krier, J
  • Kurz, N
  • Lommel, B
  • Mistry, A
  • Mokry, C
  • Omtvedt, JP
  • Papadakis, P
  • Runke, J
  • Rykaczewski, K
  • Schädel, M
  • Schaffner, H
  • Schausten, B
  • Thörle-Pospiech, P
  • Trautmann, N
  • Torres, T
  • Türler, A
  • Ward, A
  • Wiehl, N
  • Yakushev, A
  • et al.

Short-lived α-decaying nuclei "northeast" of Pb208 in the chart of nuclides were studied using the reaction Ca48+Am243 with the decay station TASISpec at TASCA, GSI Darmstadt. Decay energies and times from pile-up events were extracted with a tailor-made pulse-shape analysis routine and specific α-decay chains were identified in a correlation analysis. Decay chains starting with the even-even Ra220 and its odd-A neighbors, Fr219, and Ra221,219, with a focus on the Ra219→Rn215 decay, were studied by means of α-γ spectroscopy. A revised α-decay scheme of Ra219 is proposed, including a new decay branch from a previously not considered isomeric state at 17 keV excitation energy. Conclusions on nuclear structure are drawn from the experimental data, aided by Geant4 simulations and a discussion on theoretical calculations.

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