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Production and decay properties of the lightest osmium isotopes

A. D. Briscoe ^1,2,*, R. D. Page ¹, A. McCarter ^1,†, J. Uusitalo^2,1, S. Antalic ³, D. T. Joss ¹, K. Auranen ², M. A. M. AlAqeel ^11,1, B. Alayed^12,1 et al.

B. Andel ³, H. Ayatollahzadeh ⁴, H. Badran², L. Barber⁵, G. Beeton⁴, M. Birova ⁶, V. Bogdanoff², J. G. Cubiss ^7,‡, D. M. Cullen⁵, J. Deary⁴, U. Forsberg², T. Grahn ², P. T. Greenlees², J. B. Hilton^1,2, A. Illana ^2,§, H. Joukainen ^2,∥, D. S. Judson ¹, R. Julin ², H. Jutila ², J. M. Keatings ⁴, M. Labiche ⁸, M. Leino ², M. C. Lewis¹, J. Louko ², M. Luoma², I. Martel ^1,13, P. P. McKee⁴, P. Mosat ³, S. N. Nathaniel¹, O. Neuvonen², D. O'Donnell ⁴, J. Ojala², C. A. A. Page ⁷, J. Pakarinen ², P. Papadakis ⁸, E. Parr¹, J. Partanen^2,¶, A. M. Plaza ^2,1,**, P. Rahkila ², E. Rey-herme ⁹, P. Ruotsalainen ², J. Sarén ², J. Smallcombe ^1,††, J. F. Smith⁴, J. Sorri ^10,‡‡, C. M. Sullivan ¹, S. Szwec ², H. Tann ^1,2, A. Tolosa Delgado ², E. Uusikylä², M. Venhart⁶, L. Waring ¹, and G. L. Zimba ^2,§§

¹Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
²Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
³Department of Nuclear Physics and Biophysics, Comenius University in Bratislava, 84248 Bratislava, Slovakia
⁴School of Computing, Engineering, and Physics Sciences, University of the West of Scotland, Paisley, PA1 2BE, United Kingdom
⁵Department of Physics and Astronomy, Schuster Building, The University of Manchester, Manchester, M13 9PL, United Kingdom
⁶Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava, Slovakia
⁷School of Physics, Engineering and Technology, The University of York, York, YO10 5DD, United Kingdom
⁸Science and Technology Facilities Council, Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
⁹Irfu, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
¹⁰Sodankylä Geophysical Observatory, University of Oulu, FI-99600 Sodankylä, Finland
¹¹Physics Department, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box 90950, Riyadh, 11623, Saudi Arabia
¹²Department of Physics, College of Science, Qassim University, Buraydah, 51452, Saudi Arabia
¹³Faculty of Experimental Sciences, University of Huelva, 21071 Huelva, Spain

^*Contact author: adbrisco@liverpool.ac.uk
^†Present address: Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, 9747AA, The Netherlands.
^‡Present address: School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
^§Present address: Grupo de Física Nuclear & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, E-28040 Madrid, Spain.
^∥Present address: Department of Physics, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
^¶Deceased.
^**Present address: Center for Nuclear Study, the University of Tokyo, Hirosawa 2-1, Wako, 351-0198, Saitama, Japan.
^††Present address: Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan.
^‡‡Present address: Radiation and Nuclear Safety Authority in Finland (STUK), FI-01370 Vantaa, Finland.
^§§Present address: Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA.

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Phys. Rev. C 113, 044317 – Published 22 April, 2026

DOI: https://doi.org/10.1103/5rxb-bscn

Abstract

The production of ${}^{159, 160, 161}{Os}$ and ${}^{159, 160, 161}{Re}$ was investigated in experiments performed at the Accelerator Laboratory of the University of Jyväskylä. The nuclei of interest were produced using fusion-evaporation reactions induced by beams of 275–353 MeV ${}^{58}{Ni}$ ions bombarding a ${}^{106}{Cd}$ target. The evaporation residues were separated in flight using the recoil separator MARA and implanted into a double-sided silicon strip detector, which was used to measure their decays. Cross sections for the production of these nuclides were measured and the relative population of the $8^{+}$ isomeric states and ground states of the $N$ =84 isotones ${}^{156}{Hf}$ , ${}^{158}W$ , and ${}^{160}{Os}$ were deduced. New decay chains assigned to ${}^{160}{Os}$ were identified at beam energies of 310 and 330 MeV. These findings are compared with previous studies claiming the observation of ${}^{160}{Os}$ and ${}^{156}W$ . The $α$ decays of ${}^{161}{Os}$ were observed, confirming previous results for this nuclide and its $β$ -decaying daughter, ${}^{157}W$ . The $α$ -decay branch of ${}^{159}{Re}$ was also confirmed, but no delayed decays of this nuclide were observed that would be a signature of the $β$ decays of the as yet unknown nuclide ${}^{159}{Os}$ .

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Phys. Rev. C 113, 044317– Published 22 April, 2026

Vol. 113, Iss. 4 — April 2026

Received 19 December 2025
Accepted 23 February 2026

DOI: https://doi.org/10.1103/5rxb-bscn

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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Production and decay properties of the lightest osmium isotopes

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