[en] Initially, yields (or abundances) and branching ratios of β-delayed neutrons (βdn) from fission products (P_n-values) have had their main importance in nuclear reactor control. At that time, the six-group mathematical approximation of the time-dependence of βdn-data in terms of the so-called 'Keepin groups' was generally accepted. Later, with the development of high-resolution neutron spectroscopy, βdn data have provided important information on nuclear-structure properties at intermediate excitation energy in nuclei far from stability, as well as in nuclear astrophysics. In this paper, I will present some examples of the βdn-studies performed by the Kernchemie Mainz group during the past three decades. This work has been recognized as an example of 'broad scientific diversity' which has led to my nomination for the 2014 Hans A. Bethe prize

[en] An updated optical potential is thus provided for α-particles on nuclei within the mass number range 45≤A≤209, below the Coulomb barrier (B), on the basis of recent high-precision measurements of α-particle induced reaction data below B that made possible the understanding of actual limits and possible improvement of the α-particle optical-model potentials. The main revision concerns actually only the surface imaginary potential depth at the lowest α-particle energies well below B, and in fact only for the mass range above A∼130. A further regional point is the underestimation of reaction cross sections for the rare-earth nuclei by using the spherical optical potential unless a 7% larger value of the surface imaginary potential radius is taken into account. Involvement of this potential for further description of both the scattering and α-particles induced reactions is moreover discussed in the present work, of equal interest for nuclear astrophysics and nuclear technology for fusion devices

[en] In this contribution, we will describe neutron and proton removal from ⁹C and ⁷Be which are two particularly interesting nuclei entering the nucleo-synthesis pp-chain [1, 2]. Neutron and proton removal reactions have been used in the past twenty years to probe the single-particle structure of exotic nuclei. The core parallel-momentum distribution can give information on the angular momentum and spin of the nucleon initial state while the total removal cross section is sensitive to the asymptotic part of the initial wave function and also to the reaction mechanism. Because knockout is a peripheral reaction from which the Asymptotic Normalization Constant (ANC) of the single-particle wave function can be extracted, it has been used as an indirect method to obtain the rate of reactions like ⁸B(p,γ)⁹C or ⁷Be(p,γ)⁸B. Nucleon removal has recently been applied by the HiRA collaboration [3] to situations in which the remaining “core” is beyond the drip line, such as ⁸C and ⁶Be, unbound by one or more protons, and whose excitation-energy spectrum can be obtained by the invariant-mass method. By gating on the ground-state peak, “core” parallel-momentum distributions and total knockout cross sections have been obtained similar to previous studies with well-bound “cores”. In addition for each projectile, knock out to final bound states has also been obtained in several cases. We will report on the theoretical description and comparison to this experimental data for a few cases for which advances in the accuracy of the transfer-to-the continuum model [4, 5] have been made [6]. These include the use, when available, of “ab-initio” overlaps for the initial state [7] and in particular their ANC values [8]. Also, the construction of a nucleus-target folding potential for the treatment of the core-target S-matrix [9] using for the cores “ab-initio” densities [10] and state-of-the-art n−⁹Be optical potentials [11]. Preliminary results and open problems will be discussed

[en] The reaction ³⁴S+¹⁸⁶W at E_lab=160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The coupling of the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fission process and gives information regarding production of neutron-rich heavy nuclei. The FF–γ coincidence method is of better use then the γ – γ coincidence method when dealing with low statistic measurements and also offers the opportunity to precisely correct the Dopler shift for in-flight emitted gamma rays. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. Coincident measurements allow for discrimination between the gamma rays by accepting a specific range within the mass distribution of the reaction products. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented

[en] The ¹²C(α,γ)¹⁶O reaction at energies corresponding to the quiescent helium burning in massive stars is regarded as one of the most important processes in nuclear astrophysics. Although this process has being studied for over four decades, our knowledge of its cross section at the energies of interest for astrophysics is still widely unsatisfactory. Indeed, no experimental data are available around 300 keV and in the energy region of astrophysical interest extrapolations are performed using some theoretical approaches, usually R-matrix calculations. Consequently, the published astrophysical factors range from 1 to 288 keVb for S_E1(300) and 7 to 120 keVb for S_E2(300), especially because of the unknown contribution coming from subthreshold resonances. To improve the reliability of these extrapolations, data from complementary experiments, such as elastic and quasi- elastic α scattering on ¹²C, α-transfer reactions to ¹⁶O, and ¹⁶N decay are usually included in the analysis. Here the β-delayed α decay of ¹⁶N is used to infer information on the ¹²C(α,γ)¹⁶O reaction and a new experimental technique is suggested

[en] Elastic scattering measurements have been performed for the ⁶Li+p system in inverse kinematics at the energies of 16, 20, 25 and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS) in Catania, in the angular range between ∼2⁰ and 12⁰ in the laboratory system, giving us the possibility to span almost a full angular range in the center of mass system. Results will be presented and discussed for one of the energies

[en] Production of medical radioisotopes is one of the most important tasks in the field of nuclear technology. These radioactive isotopes are mainly produced through variety nuclear process. In this research, excitation functions and nuclear reaction mechanisms are studied for simulation of production of these radioisotopes in the TALYS, EMPIRE and LISE++ reaction codes, then parameters and different models of nuclear level density as one of the most important components in statistical reaction models are adjusted for optimum production of desired radioactive yields

[en] MINERνA (Main INjector Experiment for ν-A) is a dedicated neutrino-nucleus scattering experiment at Fermilab. It uses a fine-grained fully active detector to make precision measurements of neutrino and antineutrino interactions on a variety of different nuclear targets (plastic scintillator, C, Fe, Pb, He and H2O) for energies up to few GeV. An overview of the experiment and a description of the detector are presented

[en] In this paper, by using the SO(6) representation of eigenstates and transitional Interacting Boson Model (IBM) Hamiltonian, the evolution from prolate to oblate shapes along the chain of Hg isotopes is studied. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are found to be in good agreement with experimental data for ^200–204Hg isotopes which are supported to be located in this transitional region. (author)

[en] Accurate information about the fission barrier is important for studying of the fission process. Fission barrier is needed for discovering the island of stability in superheavy region and searching of the superheavy elements. Furthermore, the astrophysical r-process is closely related to the fission barrier of the neutron-rich nuclei. In this study, by using artificial neural network (ANN) method, we have estimated the fission barrier heights of the Rf, Db, Ra and Ac nuclei covering 230 isotopes. For inner barrier calculation, we have used Rf and Db nuclei and the barrier heights have been determined between nearly 1 MeV and 7 MeV. The related mean square error value has been obtained as 0.108 MeV. For outer barrier calculation, we have used Ra and Ac nuclei and the heights have been determined between nearly 8 MeV and 28 MeV. The related mean square error has been obtained as 0.407. The results of this study indicate that ANN is capable for the estimations of inner and outer fission barrier heights. (author)