Structure of the N=50 As, Ge, Ga nuclei

• Published in: Nuclear physics. A 2012-11, Vol.893, p.1-12
• Main Authors: Sahin, E., de Angelis, G., Duchene, G., Faul, T., Gadea, A., Lisetskiy, A.F., Ackermann, D., Algora, A., Aydin, S., Azaiez, F., Bazzacco, D., Benzoni, G., Bostan, M., Byrski, T., Celikovic, I., Chapman, R., Corradi, L., Courtin, S., Curien, D., Pramanik, U. Datta, Didierjean, F., Dorvaux, O., Erduran, M.N., Erturk, S., Farnea, E., Fioretto, E., de France, G., Franchoo, S., Gall, B., Gottardo, A., Guiot, B., Haas, F., Ibrahim, F., Ince, E., Khouaja, A., Kusoglu, A., La Rana, G., Labiche, M., Lebhertz, D., Lenzi, S., Leoni, S., Lunardi, S., Mason, P., Mengoni, D., Michelagnoli, C., Modamio, V., Montagnoli, G., Montanari, D., Moro, R., Mouginot, B., Napoli, D.R., OʼDonnell, D., Oliveira, J.R.B., Ollier, J., Orlandi, R., Pollarolo, G., Recchia, F., Robin, J., Salsac, M.-D., Scarlassara, F., Singh, R.P., Silvestri, R., Smith, J.F., Stefan, I., Stefanini, A.M., Subotic, K., Szilner, S., Tonev, D., Torres, D.A., Trotta, M., Ujic, P., Ur, C., Valiente-Dobón, J.J., Verney, D., Yalcinkaya, M., Wady, P.T., Wiedemann, K.T., Zuber, K.
• Format: Article
• Language: English
• Subjects: (fragment)γ-coin; 238U(82Se, 81Ga), (82Se, 82Ge), (82Se, 83As); [formula omitted] MeV; calculated; deduced; formula omitted; Ge Compton-suppressed detectors of CLARA array; levels; measured; Nuclear Experiment; Nuclear reactions; Physics; PRISMA magnetic spectrometer; reaction fragments; shell model; thin and thick target; γ after deexcitation; γγ-coin
• ISSN: 0375-9474; 1873-1554
• DOI: 10.1016/j.nuclphysa.2012.08.007

The level structures of the N=5083As, 82Ge, and 81Ga isotones have been investigated by means of multi-nucleon transfer reactions. A first experiment was performed with the CLARA–PRISMA setup to identify these nuclei. A second experiment was carried out with the GASP array in order to deduce the γ-ray coincidence information. The results obtained on the high-spin states of such nuclei are used to test the stability of the N=50 shell closure in the region of 78Ni (Z=28). The comparison of the experimental level schemes with the shell-model calculations yields an N=50 energy gap value of 4.7(3) MeV at Z=28. This value, in a good agreement with the prediction of the finite-range liquid-drop model as well as with the recent large-scale shell model calculations, does not support a weakening of the N=50 shell gap down to Z=28.