The half-lives of 20 neutron-rich nuclei with Z ¼ 27-30 have been measured at the RIBF, Atomic nuclei are quantum many-body systems consisting of two distinct types of fermions-protons and neutrons. Analogous to atomic physics, the concept of nuclear shell structure was triggered by the discovery of particularly stable nuclei with specific numbers of proton and neutron, such as 2, 8,20,28, 50, 82, and 126 along the β-stability line [1]. By assuming a strong spin-orbit interaction within a mean field potential, these magic numbers were correctly interpreted and regarded to be immutable throughout the nuclear chart [2,3]. However, with the development of experimental techniques exploiting radioactive ion beams, many nuclei with extreme neutron-to-proton ratios (N=Z), so-called exotic nuclei, have been produced and studied in the last few decades. The results obtained heretofore have demonstrated that the shell structure established for nuclei near the β-stability line may change drastically in these exotic nuclei. For instance, classical magic numbers in 12 Be (N ¼ 8), 32 Mg (N ¼ 20), and 42 Si (N ¼ 28) were found to disappear [4-6], whereas new magic numbers emerged in 24 O (N ¼ 16) and 54 Ca (N ¼ 34) [7][8][9]. To address the origins of shell evolution in heavier mass regions, it is of particular interest to investigate the properties of nuclei in the vicinity of 78 Ni, which has the proton number Z ¼ 28 and the neutron number N ¼ 50 with a large neutron excess N=Z ≈ 1.8.To study the shell evolution around 78 Ni, many experimental efforts have been made. One of the interesting phenomena related to the proton Z ¼ 28 shell gap is the monopole migration in Cu isotopes. A sudden drop of the excited 5=2− state relative to the ground 3=2 − state was observed in 71;73 Cu [10,11]. These two states are characterized by a single-particle nature [12] and their order was

Background: Multinucleon transfer reactions (MNT) are a competitive tool to populate exotic neutron-rich nuclei in a wide region of nuclei, where other production methods have severe limitations or cannot be used at all. Purpose: Experimental information on the yields of MNT reactions in comparison with theoretical calculations are necessary to make predictions for the production of neutron-rich heavy nuclei. It is crucial to determine the fraction of MNT reaction products which are surviving neutron emission or fission at the high excitation energy after the nucleon exchange. Method: Multinucleon transfer reactions in 136 Xe + 238 U have been measured in a high-resolution γ -ray/particle coincidence experiment. The large solid-angle magnetic spectrometer PRISMA coupled to the high-resolution Advanced Gamma Tracking Array (AGATA) has been employed. Beamlike reaction products after multinucleon transfer in the Xe region were identified and selected with the PRISMA spectrometer. Coincident particles were tagged by multichannel plate detectors placed at the grazing angle of the targetlike recoils inside the scattering chamber. Results: Mass yields have been extracted and compared with calculations based on the GRAZING model for MNT reactions. Kinematic coincidences between the binary reaction products, i.e., beamlike and targetlike nuclei, were exploited to obtain population yields for nuclei in the actinide region and compared to x-ray yields measured by AGATA. Conclusions: No sizable yield of actinide nuclei beyond Z = 93 is found to perform nuclear structure investigations. In-beam γ -ray spectroscopy is feasible for few-neutron transfer channels in U and the −2p channel populating Th isotopes.

The level structure of the neutron-rich 77 Cu nucleus is investigated through β-delayed γ-ray spectroscopy at the Radioactive Isotope Beam Factory of the RIKEN Nishina Center. Ions of 77 Ni are produced by inflight fission, separated and identified in the BigRIPS fragment separator, and implanted in the WAS3ABi silicon detector array, surrounded by Ge cluster detectors of the EURICA array. A large number of excited states in 77 Cu are identified for the first time by correlating γ rays with the β decay of 77 Ni, and a level scheme is constructed by utilizing their coincidence relationships. The good agreement between large-scale Monte Carlo shell model calculations and experimental results allows for the evaluation of the singleparticle structure near 78 Ni and suggests a single-particle nature for both the 5=2 − 1 and 3=2 The evolution of the shell structure is one of the key motivations to study atomic nuclei with large neutron excess. The goal is to understand effects due to this excess of neutrons that are responsible for deviations from the conventional harmonic oscillator description with a strong attractive spin-orbit coupling, which characterizes the shell structure and properties of nuclei near the line of β stability. Such deviations are related to the monopole components of the effective nucleon-nucleon interaction and their strong effects on the single-particle energies (SPEs). The spindependent central component influences the energies of all single-particle orbitals, while the tensor interaction alters the spin-orbit splitting when specific orbits are filled by neutrons or protons [1][2][3][4][5][6][7][8].For the chain of Ni (Z ¼ 28) isotopes between N ¼ 40 and N ¼ 50, theoretical models predict significant changes in the proton SPEs as the ν1g 9=2 shell is filled by neutrons [3,4,[9][10][11][12]. Here, the tensor force responsible for SPE shifts

The high-spin structures and isomers of the N = 81 isotones 135 Xe and 137 Ba are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in 136 Xe+ 238 U and (ii) 136 Xe+ 208 Pb MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii), in the 136 Xe+ 198 Pt MNT reaction employing the γ-ray array GAMMASPHERE in combination with the gas-detector array CHICO, and (iv) via a 11 B+ 130 Te fusion-evaporation reaction with the HORUS γ-ray array at the University of Cologne. The high-spin level schemes of 135 Xe and 137 Ba are considerably extended to higher energies. The 2058-keV (19/2 − ) state in 135 Xe is identified as an isomer, closing a gap in the systematics along the N = 81 isotones. Its half-life is measured to be 9.0(9) ns, corresponding to a reduced transition probability of B(E2, 19/2 − → 15/2 − ) = 0.52(6) W.u. The experimentally-deduced reduced transition probabilities of the isomeric states are compared to shell-model predictions. Latest shell-model calculations reproduce the experimental findings generally well and provide guidance to the interpretation of the new levels.

A highly segmented silicon-pad detector prototype has been tested to explore the performance of the digital pulse shape analysis in the discrimination of the particles reaching the silicon detector. For the first time a 200 μm thin silicon detector, grown using an ordinary floating zone technique, has been shown to exhibit a level discrimination thanks to the fine segmentation. Light-charged particles down to few MeV have been separated, including their punch-through. A coaxial HPGe detector in time coincidence has further confirmed the quality of the particle discrimination