The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N=90. To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z=56 isotopic chain accessible at present, Ba148,150, has been studied via β decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive- and negative-parity low-spin excited states of Ba150 and presents an extension of the β-decay scheme of Cs148. Employing the fast timing technique, half-lives for the 21+ level in both nuclei have been determined, resulting in T1/2=1.51(1) ns for Ba148 and T1/2=3.4(2) ns for Ba150. The systematics of low-spin states, together with the experimental determination of the B(E2:2+→0+) transition probabilities, indicate an increasing collectivity in Ba148-150, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.

Evolution of deformation in neutron-rich Ba isotopes up to A=150 / R. Licǎ, G. Benzoni, T.R. Rodríguez, M.J.G. Borge, L.M. Fraile, H. Mach, A.I. Morales, M. Madurga, C.O. Sotty, V. Vedia, H. De Witte, J. Benito, R.N. Bernard, T. Berry, A. Bracco, F. Camera, S. Ceruti, V. Charviakova, N. Cieplicka-Oryńczak, C. Costache, F.C.L. Crespi, J. Creswell, G. Fernandez-Martínez, H. Fynbo, P.T. Greenlees, I. Homm, M. Huyse, J. Jolie, V. Karayonchev, U. Köster, J. Konki, T. Kröll, J. Kurcewicz, T. Kurtukian-Nieto, I. Lazarus, M.V. Lund, N. Mǎrginean, R. Mǎrginean, C. Mihai, R.E. Mihai, A. Negret, A. Orduz, Z. Patyk, S. Pascu, V. Pucknell, P. Rahkila, E. Rapisarda, J.M. Regis, L.M. Robledo, F. Rotaru, N. Saed-Samii, V. Sánchez-Tembleque, M. Stanoiu, O. Tengblad, M. Thuerauf, A. Turturica, P. Van Duppen, N. Warr. - In: PHYSICAL REVIEW C. - ISSN 2469-9985. - 97:2(2018 Feb 05).

Evolution of deformation in neutron-rich Ba isotopes up to A=150

G. Benzoni
;
A. Bracco;F. Camera;S. Ceruti;F.C.L. Crespi;
2018

Abstract

The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N=90. To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z=56 isotopic chain accessible at present, Ba148,150, has been studied via β decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive- and negative-parity low-spin excited states of Ba150 and presents an extension of the β-decay scheme of Cs148. Employing the fast timing technique, half-lives for the 21+ level in both nuclei have been determined, resulting in T1/2=1.51(1) ns for Ba148 and T1/2=3.4(2) ns for Ba150. The systematics of low-spin states, together with the experimental determination of the B(E2:2+→0+) transition probabilities, indicate an increasing collectivity in Ba148-150, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.
nuclear and high energy physics
Settore FIS/04 - Fisica Nucleare e Subnucleare
European Nuclear Science and Application Research 2
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/572748
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