Physics Letters B (Nov 2022)

High-spin states in 212Po above the α-decaying (18+) isomer

  • L. Zago,
  • A. Gottardo,
  • J.J. Valiente-Dobón,
  • G. Benzoni,
  • A. Gadea,
  • M. Górska,
  • S. Lunardi,
  • Zs. Podolyák,
  • P.H. Regan,
  • D. Rudolph,
  • A. Algora,
  • G. de Angelis,
  • D. Bazzacco,
  • J. Benlliure,
  • P. Boutachkov,
  • A. Bracco,
  • A.M. Bruce,
  • F. Camera,
  • E. Casarejos,
  • M.L. Cortés,
  • F.C.L. Crespi,
  • A. Corsi,
  • C. Domingo-Pardo,
  • M. Doncel,
  • T. Engert,
  • H. Geissel,
  • J. Gerl,
  • A. Goasduff,
  • N. Goel,
  • J. Grebosz,
  • E. Gregor,
  • T. Habermann,
  • S. Klupp,
  • I. Kojouharov,
  • N. Kurz,
  • S.M. Lenzi,
  • S. Leoni,
  • S. Mandal,
  • R. Menegazzo,
  • D. Mengoni,
  • B. Million,
  • A.I. Morales,
  • D.R. Napoli,
  • F. Naqvi,
  • C. Nociforo,
  • M. Pfützner,
  • S. Pietri,
  • A. Prochazka,
  • F. Recchia,
  • E. Sahin,
  • H. Schaffner,
  • A. Sharma,
  • B. Sitar,
  • D. Siwal,
  • P. Strmen,
  • I. Szarka,
  • C.A. Ur,
  • P.M. Walker,
  • H. Weick,
  • O. Wieland,
  • H.-J. Wollersheim

Journal volume & issue
Vol. 834
p. 137457

Abstract

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The nucleus 212Po has been produced through the fragmentation of a 238U primary beam at 1 GeV/nucleon at GSI, separated with the FRagment Separator, FRS, and studied via isomer γ-decay spectroscopy with the RISING setup. Two delayed previously unknown γ rays have been observed. One has been attributed to the E3 decay of a 21− isomeric state feeding the α-emitting 45-s (18+) high-spin isomer. The other γ-ray line has been assigned to the decay of a higher-lying 23+ metastable state. These are the first observations of high-spin states above the 212Po (18+) isomer, by virtue of the selectivity obtained via ion-by-ion identification of 238U fragmentation products. Comparison with shell-model calculations points to shortfalls in the nuclear interactions involving high-j proton and neutron orbitals, to which the region around Z∼100 is sensitive.

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