The high-spin structures of Ba136 and Ba137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Ba136 is populated in a Xe136+U238 MNT reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and in two Be9+Te130 fusion-evaporation reactions using the High-efficiency Observatory for γ-Ray Unique Spectroscopy (HORUS) at the FN tandem accelerator of the University of Cologne, Germany. Furthermore, both isotopes are populated in an elusive reaction channel in the B11+Te130 fusion-evaporation reaction utilizing the HORUS γ-ray array. The level scheme above the Jπ=10+ isomer in Ba136 is revised and extended up to an excitation energy of approximately 5.5 MeV. From the results of angular-correlation measurements, the Ex=3707- and Ex=4920-keV states are identified as the bandheads of positive- and negative-parity cascades. While the high-spin regimes of both Te132 and Xe134 are characterized by high-energy 12+→10+ transitions, the Ba136E2 ground-state band is interrupted by negative-parity states only a few hundred keV above the Jπ=10+ isomer. Furthermore, spins are established for several hitherto unassigned high-spin states in Ba137. The new results close a gap along the high-spin structure of N<82 Ba isotopes. Experimental results are compared to large-scale shell-model calculations employing the GCN50:82, Realistic SM, PQM130, and SN100PN interactions. The calculations suggest that the bandheads of the positive-parity bands in both isotopes are predominantly of proton character.
Identification of high-spin proton configurations in Ba 136 and Ba 137 / L. Kaya, A. Vogt, P. Reiter, C. Müller-Gatermann, A. Gargano, L. Coraggio, N. Itaco, A. Blazhev, K. Arnswald, D. Bazzacco, B. Birkenbach, A. Bracco, B. Bruyneel, L. Corradi, F.C.L. Crespi, G. De Angelis, M. Droste, J. Eberth, E. Farnea, E. Fioretto, C. Fransen, A. Gadea, A. Giaz, A. Görgen, A. Gottardo, K. Hadyńska-Klȩk, H. Hess, R. Hetzenegger, R. Hirsch, P.R. John, J. Jolie, A. Jungclaus, W. Korten, S. Leoni, L. Lewandowski, S. Lunardi, R. Menegazzo, D. Mengoni, C. Michelagnoli, T. Mijatović, G. Montagnoli, D. Montanari, D. Napoli, Z. Podolyák, G. Pollarolo, F. Recchia, D. Rosiak, N. Saed-Samii, E. Şahin, M. Siciliano, F. Scarlassara, M. Seidlitz, P.-. Söderström, A.M. Stefanini, O. Stezowski, S. Szilner, B. Szpak, C. Ur, J.J. Valiente-Dobón, M. Weinert, K. Wolf, K.O. Zell. - In: PHYSICAL REVIEW C. - ISSN 2469-9985. - 99:1(2019 Jan). [10.1103/PhysRevC.99.014301]
Identification of high-spin proton configurations in Ba 136 and Ba 137
A. Bracco;F.C.L. Crespi;S. Leoni;
2019
Abstract
The high-spin structures of Ba136 and Ba137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Ba136 is populated in a Xe136+U238 MNT reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and in two Be9+Te130 fusion-evaporation reactions using the High-efficiency Observatory for γ-Ray Unique Spectroscopy (HORUS) at the FN tandem accelerator of the University of Cologne, Germany. Furthermore, both isotopes are populated in an elusive reaction channel in the B11+Te130 fusion-evaporation reaction utilizing the HORUS γ-ray array. The level scheme above the Jπ=10+ isomer in Ba136 is revised and extended up to an excitation energy of approximately 5.5 MeV. From the results of angular-correlation measurements, the Ex=3707- and Ex=4920-keV states are identified as the bandheads of positive- and negative-parity cascades. While the high-spin regimes of both Te132 and Xe134 are characterized by high-energy 12+→10+ transitions, the Ba136E2 ground-state band is interrupted by negative-parity states only a few hundred keV above the Jπ=10+ isomer. Furthermore, spins are established for several hitherto unassigned high-spin states in Ba137. The new results close a gap along the high-spin structure of N<82 Ba isotopes. Experimental results are compared to large-scale shell-model calculations employing the GCN50:82, Realistic SM, PQM130, and SN100PN interactions. The calculations suggest that the bandheads of the positive-parity bands in both isotopes are predominantly of proton character.File | Dimensione | Formato | |
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