In systematic studies of radioactive isotopes, the so-called islands of inversion appear to be promising areas of the nuclear chart in which to look for phenomena that challenge the traditional description of the atomic nucleus.

We review an extensive study of the beryllium isotopic chain carried out at RIKEN. In particular, we discuss the results on $$^{13,15}\hbox {Be}$$ , two key isotopes for the understanding of dineutron configurations and decays in $$^{14,16}\hbox {Be}$$ . In the $$^{13}$$ Be case, a detailed analysis of its spectroscopy, including for the first time a well-founded reaction framework and a realistic three-body model of $$^{14}\hbox {Be}$$ that incorporates core excitations, confirms the dominant $$\ell =1$$ content of the low-lying spectrum. In the $$^{15}$$ Be case, the fragmentation of $$^{18}$$ C, a priori free of any selection rules that may have precluded the observation of states in previous experiments, has confirmed the only known state at about 1.8 MeV, assigned according to shell-model calculations to a spin-parity $$5/2^+$$ . Some perspectives of these studies are also given.

N. Aoi, H. Baba, A. Blazhev, F. Browne, C. Campbell, M. Carpenter, A. Corsi, M.L. Cortés, H. Crawford, M. Cromaz, P. Doornenbal, P. Fallon, A. Gillibert, H. Hess, E. Ideguchi, T. Isobe, J. Jolie, V. Lapoux, H. Liu, A. Macchiavelli, O. Möller, M. Niikura, S. Nishimura, A. Obertelli, V. Panin, N. Pietralla, P. Reiter, L. Riley, H. Sakurai, M. Seidlitz, D. Suzuki, S. Thiel, V. Werner, N. Warr, K. Wimmer and Y. Yamamoto

The particle identification (PID) method based on TOF-Bρ-ΔE measurement at RIKEN are discussed, and its application for Z = 25 – 28 neutron-rich nuclei from SEASTAR (Shell Evolution And Search for Two-plus energy At RIBF) experimental data are presented. The results including the PID for beam and residual nucleus at BigRIPS and ZeroDegree, respectively, demonstrate that the reactions of interest are well separated. This ensures the precision in the data analysis later on.

MINOS is a new device composed of a thick hydrogen target and a vertex tracker [1]. It has been primarily conceived for the spectroscopy of rare isotopes produced at fragmentation facilities such as the RIKEN Radioactive Isotope Beam Facility. In the near future, MINOS in association with other detectors and spectrometers should contribute to exciting physics programs at the RIBF focusing on nuclei produced by hydrogen-induced secondary knockout reactions. The full detector and its electronics have been finalized at CEA Saclay and validated in Japan at the end of 2013. Among foreseen experiments, a scientific program named SEASTAR dedicated to the study of shell evolution and measurement of new 2^+ state energies in medium-mass unstable nuclei has been initiated at the RIBF. SEASTAR aims at exploiting the unique opportunities offered by the RIBF and the association of the high-efficiency DALI2 gamma array [2] and MINOS. The first campaign was held in May 2014. In this communication, a brief presentation of the MINOS detection system is presented as well as the intended physics program at the RIBF. A report on the first SEASTAR campaign foreseen this spring is given.

A new measurement of the dynamical dipole emission was performed in the system O-16 + Sn-116 at 12 MeV/nucleon. These data, together with those measured at 8.1 MeV/nucleon and 15.6 MeV/nucleon on the same system, provide the dependence of the dynamical dipole total emission yield on the beam energy. The energy removed by preequilibrium charged particles emission was directly measured and this made possible the direct estimation of the compound nucleus excitation energy. The experimental results show a weak increase of the dynamical dipole total yield with beam energy and they are in agreement both in trend and in absolute values with the predictions of the theoretical model based on the Boltzmann-Nordheim-Vlasov approach. The measured gamma-ray angular distribution has a dipole character but with a strong quenching probably owing to the rotation of the dipolar axis during the fusion and thermalization processes.

In heavy ion reactions, in the case of N/Z asymmetry between projectile and target, the process leading to complete fusion is expected to produce pre-equilibrium dipole γ -ray emission. It is generated during the charge equilibration process and it is known as Dynamical Dipole. A new measurement of the dynamical dipole emission was performed by studying 16 O + 116 Sn at 12 MeV/u. These data, together with those measured at 8.1 MeV/u and 15.6 MeV/u for the same reaction, provide the dependence on the Dynamical Dipole total emission yield with beam energy and they can be compared with theoretical expectations. The experimental results show a weak increase of the Dynamical Dipole total yield with beam energies and are in agreement with the prediction of a theoretical model based on the Boltzmann–Nordheim–Vlasov (BNV) approach. The measured trend with beam energy does not confirm the rise and fall behavior previously reported for the same fused compound but with a much higher dipole moment.

Neutron-rich isotopes around lead, beyond N=126, have been studied exploiting the fragmentation of an uranium primary beam at the FRS-RISING setup at GSI. For the first time β-decay half-lives of Bi219 and Tl211,212,213 isotopes have been derived. The half-lives have been extracted using a numerical simulation developed for experiments in high-background conditions. Comparison with state of the art models used in r-process calculations is given, showing a systematic underestimation of the experimental values, at variance from close-lying nuclei.

1 INFN, Sezione di Firenze, Firenze, Italy. 2 Dipartimento di Fisica, Università di Firenze, Firenze, Italy. 3 INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy. 4 INFN, Sezione di Bologna, Bologna, Italy. 5 Dipartimento di Fisica, Università di Bologna, Bologna, Italy. 6 INFN, Sezione di Milano, Milano, Italy. 7 Dipartimento di Fisica, Università di Milano, Milano, Italy. 8 IFJ, PAN Krakow, Krakow, Poland. 9 University of Science, Physics Department, Nevsheir, Turkey. ⋆ present address: INFN, Sezione di Catania, Catania, Italy.

The gamma decay associated with the warm rotation of the superdeformed nuclei Tb-151 and Pb-196 has been measured with the Euroball IV array. Several experimental quantities are presented, putting strong constraints on the decay dynamics in the superdeformed well. The data are successfully reproduced using a Monte Carlo simulation of the gamma decay based on microscopically calculated energy levels, E2 decay probabilities, collective mass parameters, and potential energy barriers between the wells associated with normal and super deformation. This allows one to test the basic ingredients of the physical process, such as the strength of the two-body residual interaction and the potential barriers as a function of spin and excitation energy. We also show that the data probe the E1 strength function, indicating an enhancement around 1-2 MeV gamma rays, which might be related to octupole vibrations. .

D. Montanari, S. Leoni, G. Benzoni, N. Blasi, A. Bracco S. Brambilla, F. Camera, A. Corsi, F.C.L. Crespi B. Million, R. Nicolini, O. Wieland, L. Corradi G. de Angelis, F. Della Vedova, E. Fioretto, A. Gadea B. Guiot, D.R. Napoli, R. Orlandi, F. Recchia R. Silvestri, A.M. Stefanini, R.P. Singh, S. Szilner J.J. Valiente-Dobón, D. Bazzacco, E. Farnea, S.M. Lenzi S. Lunardi, P. Mason, D. Mengoni, G. Montagnoli F. Scarlassara, C. Ur, G. Lo Bianco , A. Zucchiatti M. Kmiecik, A. Maj, W. Meczynski, G. Pollarolo

D.Montanari, G.Benzoni, N.Blasi, A.Bracco, S.Brambilla, F.Camera, A.Corsi, F.C.L.Crespi, S.Leoni, B.Million, R.Nicolini, O.Wieland, G.Pollarolo, L.Corradi, G.de Angelis, F.Della Vedova, E.Fioretto, A.Gadea, B.Guiot, D.Napoli, R.Orlandi, F.Recchia, R.Silvestri, A.M.Stefanini, R.P.Singh, S.Szilner, J.J.Valiente-Dobón, S.Beghini, D.Bazzacco, E.Farnea, S.M.Lenzi, S.Lunardi, P.Mason, D.Mengoni, G.Montagnoli, F.Scarlassara, C.Ur, G.Lo Bianco, A.Zucchiatti, M.Kmiecik, A.Maj, W.Meczynski Università degli Studi e INFN sezione di Milano, Dipartimento di Fisca Teorica, Università di Torino e INFN sezione di Torino, Torino, Italy, INFN Laboratori Nazionali di Legnaro, Legnaro (Pd), Italy, RBI, Zagreb, Croatia, Università di Padova e INFN sezione di Padova, Padova, Italy, Università di Camerino e INFN sezione di Perugia, Camerino (Pg), Italy, INFN sezione di Genova, Genova, Italy, The Niewodniczanski Institute of Nuclear Physics, PAN, Krakow, Poland.

Contaminated groundwater typically contains different metal contaminants which may compete with each other for the same adsorption sites. Understanding the fate of these micro-pollutants is of primary importance for the assessment of the risk associated with their dispersion in the environment and for the evaluation of the most appropriate remediation technology. In this regard, column techniques can be considered as useful tools both to perform transport experiments and to obtain equilibrium adsorption data without any perturbation of the actual solid/liquid interface. Cd and Pb monocomponent step column experiments were used to obtain adsorption isotherms on a natural aquifer material. A General Composite approach was used to define the equilibrium adsorption model characterized by two types of sites (ion-exchange and surface complexation sites). Coupling the adsorption model with the AdvectionDispersion equation (by IMPACT code) allowed us to well represent the monocomponent step experiments. The model was successfully used to predict the competitive Cd and Pb transport behaviour. Cd peaks of concentration due to Pb competition were experimentally observed and simulated by the model. This behaviour can be described only by an accurate modelling of the interaction and cannot be predicted by simple isotherms (such as Langmuir or Freundlich type).