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

A. Såmark-Roth, L. G. Sarmiento, D. Rudolph, J. Ljungberg, B. G. Carlsson, C. Fahlander, U. Forsberg, P. Golubev, I. Ragnarsson, D. Ackermann, L. Andersson, M. Block, H. Brand, D. M. Cox, A. Di Nitto, Ch. E. Düllmann, K. Eberhardt, J. Even, J. M. Gates, J. GerlK. E. Gregorich, C. J. Gross, R. Herzberg, F. P. Heßberger, E. Jäger, J. Khuyagbaatar, B. Kindler, I. Kojouharov, J. V. Kratz, J. Krier, N. Kurz, B. Lommel, A. Mistry, C. Mokry, J. P. Omtvedt, P. Papadakis, J. Runke, K. Rykaczewski, M. Schädel, H. Schaffner, B. Schausten, N. Trautmann, T. Torres, A. Türler, A. Ward, N. Wiehl, A. Yakushev

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Short-lived α-decaying nuclei “northeast” of 208Pb in the chart of nuclides were studied using the reaction 48Ca+243Am 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 220Ra and its odd-A neighbors, 219Fr, and 221,219Ra, with a focus on the 219Ra→215Rn decay, were studied by means of α−γ spectroscopy. A revised α-decay scheme of 219Ra 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.
Original languageEnglish
Article number044307
Number of pages11
JournalPhysical Review C
Issue number4
Publication statusPublished - 9-Oct-2018
Externally publishedYes


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