In-beam γ -ray spectroscopy of the neutron-rich platinum isotope Pt 200 toward the N = 126 shell gap

• Published in: Physical review. C 2017-06, Vol.95 (6), Article 064321
• Main Authors: John, P. R., Valiente-Dobón, J. J., Mengoni, D., Modamio, V., Lunardi, S., Bazzacco, D., Gadea, A., Wheldon, C., Rodríguez, T. R., Alexander, T., de Angelis, G., Ashwood, N., Barr, M., Benzoni, G., Birkenbach, B., Bizzeti, P. G., Bizzeti-Sona, A. M., Bottoni, S., Bowry, M., Bracco, A., Browne, F., Bunce, M., Camera, F., Corradi, L., Crespi, F. C. L., Melon, B., Farnea, E., Fioretto, E., Gottardo, A., Grente, L., Hess, H., Kokalova, Tz, Korten, W., Kuşoğlu, A., Lenzi, S., Leoni, S., Ljungvall, J., Menegazzo, R., Michelagnoli, C., Mijatović, T., Montagnoli, G., Montanari, D., Napoli, D. R., Podolyák, Zs, Pollarolo, G., Recchia, F., Reiter, P., Roberts, O. J., Şahin, E., Salsac, M.-D., Scarlassara, F., Sferrazza, M., Söderström, P.-A., Stefanini, A. M., Szilner, S., Ur, C. A., Vogt, A., Walshe, J.
• Format: Article
• Language: English
• ISSN: 2469-9985; 2469-9993; 2469-9993
• DOI: 10.1103/PhysRevC.95.064321

The neutron-rich nucleus Pt-200 is investigated via in-beam gamma-ray spectroscopy to study the shape evolution in the neutron-rich platinum isotopes towards the N = 126 shell closure. The two-neutron transfer reaction Pt-198(Se-82, Se-80)Pt-200 is used to populate excited states of Pt-200. The Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with the PRISMA spectrometer detects gamma rays coincident with the Se-80 recoils, the binary partner of Pt-200. The binary partner method is applied to extract the gamma-ray transitions and build the level scheme of Pt-200. The level at 1884 keV reported by Yates et al. [S. W. Yates, E. M. Baum, E. A. Henry, L. G. Mann, N. Roy, A. Aprahamian, R. A. Meyer, and R. Estep, Phys. Rev. C 37, 1889 (1988)] was confirmed to be at 1882.1 keV and assigned as the (6(1)(+)) state. An additional gamma ray was found and it presumably deexcites the (8(1)(+)) state. The results are compared with state-of-the-art beyond mean-field calculations, performed for the even-even Pt190-204 isotopes, revealing that Pt-200 marks the transition from the gamma-unstable behavior of lighter Pt nuclei towards a more spherical one when approaching the N = 126 shell closure.