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Title: Shape coexistence in the odd-odd nucleus Y 98 : The role of the g 9 / 2 neutron extruder

Abstract

Excited states in Y-98, populated in neutron-induced fission of U-235 and in spontaneous fission of Cm-248 and Cf-252, have been studied by means of gamma spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in Y-98: a deformed one with T-1/2 = 180(7) ns and a rotational band on top of it, and a spherical one with T-1/2 = 0.45(15) mu s, analogous to the 8(+) isomer in Y-96, corresponding to the (nu g(7/2), pi g(9/2))(8+) spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in Y-98. This result and the studies of excited levels in Zr-98, populated in beta-decay of the isomer, indicate a new spin-parity, I-pi = (7)(+) for the isomer. The high spin and the decay properties of this isomer suggest the presence of the 9/2(+)[ 404] neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the nu g(7/2)-pi g(9/2) interaction (the spin-orbit-partner, or SOP, mechanism).

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
Polish National Science Centre (NCN); USDOE Office of Science - Office of Nuclear Physics
OSTI Identifier:
1422551
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 96; Journal Issue: 4; Journal ID: ISSN 2469-9985
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

Citation Formats

Urban, W., Czerwiński, M., Kurpeta, J., Rząca-Urban, T., Wiśniewski, J., Materna, T., Iskra, Ł. W., Smith, A. G., Ahmad, I., Blanc, A., Faust, H., Köster, U., Jentschel, M., Mutti, P., Soldner, T., Simpson, G. S., Pinston, J. A., de France, G., Ur, C. A., Elomaa, V. -V., Eronen, T., Hakala, J., Jokinen, A., Kankainen, A., Moore, I. D., Rissanen, J., Saastamoinen, A., Szerypo, J., Weber, C., and Äystö, J. Shape coexistence in the odd-odd nucleus Y98 : The role of the g9/2 neutron extruder. United States: N. p., 2017. Web. doi:10.1103/PhysRevC.96.044333.
Urban, W., Czerwiński, M., Kurpeta, J., Rząca-Urban, T., Wiśniewski, J., Materna, T., Iskra, Ł. W., Smith, A. G., Ahmad, I., Blanc, A., Faust, H., Köster, U., Jentschel, M., Mutti, P., Soldner, T., Simpson, G. S., Pinston, J. A., de France, G., Ur, C. A., Elomaa, V. -V., Eronen, T., Hakala, J., Jokinen, A., Kankainen, A., Moore, I. D., Rissanen, J., Saastamoinen, A., Szerypo, J., Weber, C., & Äystö, J. Shape coexistence in the odd-odd nucleus Y98 : The role of the g9/2 neutron extruder. United States. doi:10.1103/PhysRevC.96.044333.
Urban, W., Czerwiński, M., Kurpeta, J., Rząca-Urban, T., Wiśniewski, J., Materna, T., Iskra, Ł. W., Smith, A. G., Ahmad, I., Blanc, A., Faust, H., Köster, U., Jentschel, M., Mutti, P., Soldner, T., Simpson, G. S., Pinston, J. A., de France, G., Ur, C. A., Elomaa, V. -V., Eronen, T., Hakala, J., Jokinen, A., Kankainen, A., Moore, I. D., Rissanen, J., Saastamoinen, A., Szerypo, J., Weber, C., and Äystö, J. Sun . "Shape coexistence in the odd-odd nucleus Y98 : The role of the g9/2 neutron extruder". United States. doi:10.1103/PhysRevC.96.044333.
@article{osti_1422551,
title = {Shape coexistence in the odd-odd nucleus Y98 : The role of the g9/2 neutron extruder},
author = {Urban, W. and Czerwiński, M. and Kurpeta, J. and Rząca-Urban, T. and Wiśniewski, J. and Materna, T. and Iskra, Ł. W. and Smith, A. G. and Ahmad, I. and Blanc, A. and Faust, H. and Köster, U. and Jentschel, M. and Mutti, P. and Soldner, T. and Simpson, G. S. and Pinston, J. A. and de France, G. and Ur, C. A. and Elomaa, V. -V. and Eronen, T. and Hakala, J. and Jokinen, A. and Kankainen, A. and Moore, I. D. and Rissanen, J. and Saastamoinen, A. and Szerypo, J. and Weber, C. and Äystö, J.},
abstractNote = {Excited states in Y-98, populated in neutron-induced fission of U-235 and in spontaneous fission of Cm-248 and Cf-252, have been studied by means of gamma spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in Y-98: a deformed one with T-1/2 = 180(7) ns and a rotational band on top of it, and a spherical one with T-1/2 = 0.45(15) mu s, analogous to the 8(+) isomer in Y-96, corresponding to the (nu g(7/2), pi g(9/2))(8+) spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in Y-98. This result and the studies of excited levels in Zr-98, populated in beta-decay of the isomer, indicate a new spin-parity, I-pi = (7)(+) for the isomer. The high spin and the decay properties of this isomer suggest the presence of the 9/2(+)[ 404] neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the nu g(7/2)-pi g(9/2) interaction (the spin-orbit-partner, or SOP, mechanism).},
doi = {10.1103/PhysRevC.96.044333},
journal = {Physical Review C},
issn = {2469-9985},
number = 4,
volume = 96,
place = {United States},
year = {2017},
month = {10}
}

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