Browsing by Subject "GAMMA-RAY SPECTROSCOPY"

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  • Kesteloot, N.; Bastin, B.; Gaffney, L. P.; Wrzosek-Lipska, K.; Auranen, K.; Bauer, C.; Bender, M.; Bildstein, V.; Blazhev, A.; Boenig, S.; Bree, N.; Clement, E.; Cocolios, T. E.; Damyanova, A.; Darby, I.; De Witte, H.; Di Julio, D.; Diriken, J.; Fransen, C.; Garcia-Ramos, J. E.; Gernhaeuser, R.; Grahn, T.; Heenen, P. -H.; Hess, H.; Heyde, K.; Huyse, M.; Iwanicki, J.; Jakobsson, U.; Konki, J.; Kroell, T.; Laurent, B.; Lecesne, N.; Lutter, R.; Pakarinen, J.; Peura, P.; Piselli, E.; Prochniak, L.; Rahkila, P.; Rapisarda, E.; Reiter, P.; Scheck, M.; Seidlitz, M.; Sferrazza, M.; Siebeck, B.; Sjodin, M.; Tornqvist, H.; Traykov, E.; Van De Walle, J.; Van Duppen, P.; Vermeulen, M.; Voulot, D.; Warr, N.; Wenander, F.; Wimmer, K.; Zielinska, M. (2015)
    Coulomb-excitation experiments are performed with postaccelerated beams of neutron-deficient Po-196,Po-198,Po-200,Po-202 isotopes at the REX-ISOLDE facility. A set of matrix elements, coupling the low-lying states in these isotopes, is extracted. In the two heaviest isotopes, Po-196,Po-198, the transitional and diagonal matrix elements of the 2(1)(+) state are determined. In Po-196,Po-198 multistep Coulomb excitation is observed, populating the 4(1)(+), 0(2)(+), and 2(2)(+) states. The experimental results are compared to the results from the measurement of mean-square charge radii in polonium isotopes, confirming the onset of deformation from Po-196 onwards. Three model descriptions are used to compare to the data. Calculations with the beyond-mean-field model, the interacting boson model, and the general Bohr Hamiltonian model show partial agreement with the experimental data. Finally, calculations with a phenomenological two-level mixing model hint at the mixing of a spherical structure with a weakly deformed rotational structure.
  • Ertoprak, A.; Cederwall, B.; Qi, C.; Aktas, O.; Doncel, M.; Hadinia, B.; Liotta, R.; Sandzelius, M.; Scholey, C.; Andgren, K.; Back, T.; Badran, H.; Braunroth, T.; Calverley, T.; Cox, D. M.; Cullen, D. M.; Fang, Y. D.; Ganioglu, E.; Giles, M.; Gomez Hornillos, M. B.; Grahn, T.; Greenlees, P. T.; Hilton, J.; Hodge, D.; Ideguchi, E.; Jakobsson, U.; Johnson, A.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Khaplanov, A.; Kumar Raju, M.; Leino, M.; Li, H.; Liu, H.; Matta, S.; Modamio, V.; Nara Singh, B. S.; Niikura, M.; Nyman, M.; Ozgur, I.; Page, R. D.; Pakarinen, J.; Papadakis, P.; Partanen, J.; Paul, E. S.; Petrache, C. M.; Peura, P.; Rahkila, P.; Ruotsalainen, P.; Saren, J.; Sorri, J.; Stolze, S.; Subramaniam, P.; Taylor, M. J.; Uusitalo, J.; Valiente-Dobon, J. J.; Wyss, R. (2020)
    Excited states in the extremely neutron-deficient nucleus Pt-172 were populated via Ru-96(Kr-78, 2p) and Mo-92(Kr-83, 3n) reactions. The level scheme has been extended up to an excitation energy of approximate to 5MeV and tentative spin-parity assignments up to I-pi = 18(+). Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negativeparity band. The lowestmember of this negative-parity structure was firmly assigned spin-parity 3(-). In addition, we observed an E3 transition from this 3(-) state to the ground state, providing direct evidence for octupole collectivity in Pt-172. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3(-) state as a collective octupole-vibrational state.
  • Konki, J.; Sulignano, B.; Greenlees, P. T.; Theisen, Ch.; Auranen, K.; Badran, H.; Briselet, R.; Cox, D. M.; Bisso, F. Defranchi; Dobaczewski, J.; Grahn, T.; Herzan, A.; Herzberg, R. -D.; Julin, R.; Juutinen, S.; Khuyagbaatar, J.; Leino, M.; Lightfoot, A.; Pakarinen, J.; Papadakis, P.; Partanen, J.; Rahkila, P.; Sandzelius, M.; Saren, J.; Scholey, C.; Shi, Y.; Smolen, M.; Sorri, J.; Stolze, S.; Uusitalo, J. (2018)
    The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244Cf was identified for the first time and measured up to a tentative spin and parity of I I-pi = 20(+). The observation of the rotational band indicates that the nucleus is deformed. The kinematic and dynamic moments of inertia were deduced from the measured gamma-ray transition energies. The behavior of the dynamic moment of inertia revealed an up-bend due to a possible alignment of coupled nucleons in high-j orbitals starting at a rotational frequency of about (h) over bar (omega) = 0.20 MeV. The results were compared with the systematic behavior of the even-even N = 146 isotones as well as with available theoretical calculations that have been performed for nuclei in the region.