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Reinterpretation of excited states in 212Po: Shell-model multiplets rather than α-cluster states

Fernández, A. ; Jungclaus, A. ; Golubev, P. LU ; Rudolph, D. LU orcid ; Sarmiento, L. G. LU ; Gargano, A. ; Naïdja, H. ; Astier, A. ; Dupont, E. and Gadea, A. , et al. (2021) In Physical Review C 104(5).
Abstract
A γ-ray spectroscopic study of 212Po was performed at the Grand Accélérateur National d'Ions Lourds, using the inverse kinematics α-transfer reaction 12C(208Pb,212Po)8Be and the AGATA spectrometer. A careful analysis based on γγ coincidence relations allowed us to establish 14 new excited states in the energy range between 1.9 and 3.3 MeV. None of these states, however, can be considered as candidates for the levels with spins and parities of 1 and 2 and excitation energies below 2.1 MeV, which have been predicted by recent α-cluster model calculations. A systematic comparison of the experimentally established excitation scheme of 212Po with... (More)
A γ-ray spectroscopic study of 212Po was performed at the Grand Accélérateur National d'Ions Lourds, using the inverse kinematics α-transfer reaction 12C(208Pb,212Po)8Be and the AGATA spectrometer. A careful analysis based on γγ coincidence relations allowed us to establish 14 new excited states in the energy range between 1.9 and 3.3 MeV. None of these states, however, can be considered as candidates for the levels with spins and parities of 1 and 2 and excitation energies below 2.1 MeV, which have been predicted by recent α-cluster model calculations. A systematic comparison of the experimentally established excitation scheme of 212Po with shell-model calculations was performed. This comparison suggests that the six states with excitation energies (spins and parities) of 1744 (4), 1751 (8), 1787 (6), 1946 (4), 1986 (8), and 2016 (6) keV, which previously were interpreted as α-cluster states, may in fact be of positive parity and belong to low-lying shell-model multiplets. This reinterpretation of the structure of 212Po is supported by experimental information with respect to the linear polarization of γ rays, which suggests a magnetic character of the 432-keV γ ray decaying from the state at an excitation energy of 1787 keV to the 6+ yrast state, and exclusive reaction cross sections. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
nuclear structure, shell-model calculations, alpha cluster states, AGATA, linear polarisation
in
Physical Review C
volume
104
issue
5
article number
054316
pages
19 pages
publisher
American Physical Society
external identifiers
  • scopus:85120539860
ISSN
2469-9985
DOI
10.1103/PhysRevC.104.054316
project
Nuclear Structure at the Limits: Isotope-selective Spectroscopy
language
English
LU publication?
yes
id
cb338118-7cd1-4eee-8456-72f1dc024314
date added to LUP
2021-11-30 18:49:39
date last changed
2022-05-05 06:17:19
@article{cb338118-7cd1-4eee-8456-72f1dc024314,
  abstract     = {{A γ-ray spectroscopic study of <sup>212</sup>Po was performed at the Grand Accélérateur National d'Ions Lourds, using the inverse kinematics α-transfer reaction <sup>12</sup>C(<sup>208</sup>Pb,<sup>212</sup>Po)<sup>8</sup>Be and the AGATA spectrometer. A careful analysis based on γγ coincidence relations allowed us to establish 14 new excited states in the energy range between 1.9 and 3.3 MeV. None of these states, however, can be considered as candidates for the levels with spins and parities of 1<sup>−</sup> and 2<sup>−</sup> and excitation energies below 2.1 MeV, which have been predicted by recent α-cluster model calculations. A systematic comparison of the experimentally established excitation scheme of <sup>212</sup>Po with shell-model calculations was performed. This comparison suggests that the six states with excitation energies (spins and parities) of 1744 (4<sup>−</sup>), 1751 (8<sup>−</sup>), 1787 (6<sup>−</sup>), 1946 (4<sup>−</sup>), 1986 (8<sup>−</sup>), and 2016 (6<sup>−</sup>) keV, which previously were interpreted as α-cluster states, may in fact be of positive parity and belong to low-lying shell-model multiplets. This reinterpretation of the structure of <sup>212</sup>Po is supported by experimental information with respect to the linear polarization of γ rays, which suggests a magnetic character of the 432-keV γ ray decaying from the state at an excitation energy of 1787 keV to the 6<sup>+</sup> yrast state, and exclusive reaction cross sections.}},
  author       = {{Fernández, A. and Jungclaus, A. and Golubev, P. and Rudolph, D. and Sarmiento, L. G. and Gargano, A. and Naïdja, H. and Astier, A. and Dupont, E. and Gadea, A. and Nácher, E. and Perea, A. and Wimmer, K. and Clément, E. and Fremont, G. and Goupil, J. and Houarner, C. and Jacquot, B. and Korichi, A. and Lemasson, A. and Li, H. J. and Ljungvall, J. and Ménager, L. and Pérez-Vidal, R. M. and Petrache, C. M. and Ralet, D. and Ropert, J. A. and Saillant, F. and Såmark-Roth, A. and Simpson, G. S. and Spitaels, C. and Zielinska, M. and Ansari, S. and Dudouet, J. and Illana, A. and Jurado, M. and Kocheva, D. and Lalović, N. and Lorenz, Ch. and Quintana, B. and Rainovski, G. and Redon, N. and Tocabens, G. and Barrientos, D. and Benzoni, G. and Birkenbach, B. and Boston, A. J. and Boston, H. C. and Bracco, A. and Ciemala, M. and Collado, J. and Cullen, D. M. and Domingo-Pardo, C. and Eberth, J. and González, V. and Harkness-Brennan, L. J. and Hess, H. and Judson, D. S. and Korten, W. and Leoni, S. and Maj, A. and Menegazzo, R. and Mengoni, D. and Michelagnoli, C. and Million, B. and Napoli, D. R. and Nyberg, J. and Podolyak, Zs. and Pullia, A. and Reiter, P. and Sanchis, E. and Stezowski, O. and Theisen, Ch. and Valiente-Dobón, J. J.}},
  issn         = {{2469-9985}},
  keywords     = {{nuclear structure; shell-model calculations; alpha cluster states; AGATA; linear polarisation}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{5}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review C}},
  title        = {{Reinterpretation of excited states in <sup>212</sup>Po: Shell-model multiplets rather than α-cluster states}},
  url          = {{https://lup.lub.lu.se/search/files/110358063/PhysRevC.104.054316.pdf}},
  doi          = {{10.1103/PhysRevC.104.054316}},
  volume       = {{104}},
  year         = {{2021}},
}