Study of N=50, Z=28 shell closures around 78Ni using high-intensity stable beams at Laboratori Nazionali di Legnaro

by Dr Eda Sahin (University of Oslo, Dept. of Physics, Norway)

Tuesday 2 Oct 2012, 10:30 → 11:30 Europe/Rome

Direction meeting room (INFN-LNL)

Two experimental studies in order to study N=50 and Z=28 shell gaps in the region of 78Ni have been carried out at Laboratori Nazionali di Legnaro, LNL. In the first work, the level structures of the N = 50 83As, 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. The work was followed by a complementary thick-target experiment using the GASP array in order to deduce the gamma-ray coincidence information. The results obtained on the high-spin states of such nuclei to test the stability of the N = 50 shell closure in the region of 78Ni (Z = 28) will be discussed in the seminar. In the second work, neutron-rich Cu isotopes have been populated via a multi-nucleon transfer reaction of a 76Ge beam onto a thin 238U target. Data have been taken using the AGATA Demonstrator array coupled to the PRISMA magnetic spectrometer. Lifetimes of the excited states in Cu nuclei have been measured by the Cologne Differantial Plunger dedicated to the usage of the AGATA Demonstrator with the PRISMA spectrometer at LNL. The knowledge of the electromagnetic transition matrix elements deexciting the states of interest in Cu nuclei, obtained through lifetime measurements, will provide determination of the collective or single-particle character of these states, therefore the essential information on the shell gap size and evolution of the Z=28 shell gap around 78Ni. The results and their comparison with the large-scale shell model predictions will be discussed in the seminar.