Excited states in 217Ra populated in the α decay of 221Th

E. Parr*, J. F. Smith, P. T. Greenlees, K. Auranen, R. Chapman, D. M. Cullen, T. Grahn, L. Grocutt, A. Herzáň, R.-D. Herzberg, D. Hodge, U. Jakobsson, R. Julin, S. Juutinen, J. Konki, C. McPeake, D. Mengoni, A. K. Mistry, K. F. Mulholland, G. G. O'NeillJ. Pakarinen, P. Papadakis, J. Partanen, P. Peura, P. Rahkila, P. Ruotsalainen, M. Sandzelius, J. Saren, M. Scheck, C. Scholey, M. Siciliano, M. Smolen, J. Sorri, S. Stolze, M. J. Taylor, J. Uusitalo

*Corresponding author for this work

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Fine structure in the α decay of 22190Th, populating excited states in 21788Ra, was studied using αγ-coincidence spectroscopy. Two α-decay branches from 221Th have been newly observed, with Eα(keV)[bα(%)]=7951(8)[0.14(3)] and 8247(3)[1.51(12)], together with three previously known branches. Also, two new states in 217Ra were identified at E = 177 and 227 keV. The ground-state configurations of the odd-A, N = 131 transitional isotones above 208Pb are interpreted from their α-decay fine structure systematics and considered in terms of predictions using spherical shell and reflection-asymmetric models.
Original languageEnglish
Article number054335
JournalPhysical Review C
Issue number5
Publication statusPublished - 30 Nov 2020


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