Study of decay properties for Ba to Nd nuclei relevant for the formation of the r-process rare-earth peak (A∼160)

¹ Institut de Tècniques Energètiques (INTE), Universitat Politècnica de Catalunya (UPC), 08028 Barcelona, Spain.
² Instituto de Física Corpuscular (IFIC), CSIC-UV, E-46980 Paterna, Spain.
³ Institute for Nuclear Research (ATOMKI), 4026 Debrecen, Bem tér 18/c, Hungary.
⁴ University of Debrecen, 4032 Debrecen, Egyetem tér 1, Hungary.
⁵ Department of Physics, University of Jyväskylä, Finland.
⁶ Centro de Investigación en Física Nuclear y Espectroscopía de Neutrones (CEFNEN). Comisión Chilena de Energía Nuclear, Nueva Bilbao 12501, Las Condes, Santiago-Chile.
⁷ Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
⁸ RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
⁹ Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
¹⁰ TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada.
¹¹ STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom.
¹² School of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
¹³ Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2, Canada.
¹⁴ Central Michigan University, Mt. Pleasant, MI 48859, USA.
¹⁵ Department of Physics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
¹⁶ Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0106, Japan.
¹⁷ Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom.
¹⁸ Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
¹⁹ Department of Physics, the University of Hong Kong, Pokfulam Road, Hong Kong.
²⁰ Department of Physics and Astronomy, The University of British Columbia, Vancouver BC V6T 1Z1, Canada.
²¹ Heavy Ion Laboratory, University of Warsaw, Pasteura 5A, 02-093 Warsaw, Poland.
²² www.wiki.ed.ac.uk/display/BRIKEN/Home

^* max.pallas@upc.edu
^† atarisal@ific.uv.es

Published online: 22 March 2023

Abstract

At the RIKEN Nishina Center, exotic neutron-rich isotopes of Ba, La, Ce, Pr, and Nd were measured. This work reports their half-lives (T_1/2) and β-delayed neutron-emission probabilities (P_xn). The setup consisted of the BigRIPS in-flight separator for particle identification, the Advanced Implantation Detector Array (AIDA) for ions and β detection, and the BRIKEN neutron counter for neutron detection. Using this arrangement, 4 new T_1/2 and 14 new P_1n were measured. Furthermore, 38 T_1/2 and 2 P_1n values were remeasured, decreasing the uncertainties for some of them. In addition to improving predictions of nucleosynthesis models that describe the production of the rare-earth peak at A ∼ 160 via the r-process, these additional experimental data should help to constrain theoretical models for calculations of T_1/2 and P_xn in this region.