[en] The three dimensional Total Routhian Surface (TRS) calculations are carried out for 64 nuclei in the 70≤A≤90 region to find triaxial superdeformed nuclei. A total of 12 nuclei are predicted to have triaxial superdeformation in which the neutron rotational energy plays a key role and the neutron shell energy plays additional role in the formation of triaxial superdeformed nuclei. (authors)

[en] The growth behavior of the Kr bubbles in Kr⁺ irradiated Zr–1.1Nb–1.51Fe–0.26Cu–0.72Ni alloy was studied by in situ transmission electron microscopy. Results show that the distributions of Kr bubbles are not uniform in the zirconium alloy matrix after annealing at 700 K, 875 K, 1025 K, 1125 K and 1225 K, respectively. The Kr bubbles started to grow slowly when the sample was annealed at a temperature below 1025 K. The average sizes of the gas bubbles were observed to grow only about 0.4 nm in diameter at 700 K for 170 min and 0.9 nm at 875 K for 240 min, respectively. However, gas bubbles grew very quickly at 1225 K. The largest size of the gas bubbles is over 200 nm after 180 min annealing. The relationship between the bubble size and the annealing time was obtained at the designed annealing temperature. An empirical formula for calculating the bubble size was suggested by fitting equations derived from the experiment data. Finally, the growth mechanism of the bubbles in the zirconium alloy was discussed

[en] The ternary decay in "2"5"2Cf(sf, fff), with three cluster fragments of different masses (e.g."1"3"2Sn,"5"2"-"4"8Ca,"6"8"-"7"2Ni), has been observed by the FOBOS group in JINR. This work has established a new decay mode of heavy nuclei, the collinear cluster tripartition, (CCT). This ''true ternary fission'' of heavy nuclei has been predicted many times in theoretical works during the last decades. In the present report we discuss true ternary fission (FFF) into three nuclei of almost equal size (e.g. Z=98 → Z_i = 32, 34, 32) and other fission modes in the same system. The possible fission channels for "2"5"2 Cf(sf) are predicted from potential-energy (PES) calculations. These PES's show pronounced minima for several ternary fragmentation decays, suggesting a variety of collinear ternary fission modes. The FFF-decays have very similar dynamical features as the previously observed collinear CCT-decays, the central fragment has very small kinetic energy. The data of the cited experiment allow the extraction of the yield for some FFF-decays, by using specific gates on the measured parameters

[en] The shell model predictions for even ^68-76Ni isotopes and odd-A Cu isotopes with newly derived effective interaction for the f_5/2p_3/2p_1/2g_9/2 model space are presented. (orig.)

[en] Starting from the T45 Skyrme interaction with tensor terms, the properties of the β-decay of "7"2"-"8"0Ni are studied. We take into account the effect of unpaired neutron and proton on the ground state properties of odd-odd and even-odd nuclei. It is shown that the calculated Q_β values and the β-decay half-lives are in a reasonable agreement with experimental data.

[en] Full text: Shape-transitional phenomena are indicators of alterations in the normal-order configuration of protons and neutrons. For exotic nuclei, they may prelude the discovery of new nuclear regions in which the ground states are dominated by deformed intruder configurations, the so- called islands of inversion. Shape transitions can also take place with excitation energy or angular momentum, leading to the coexistence of different shapes within the same nucleus. The nuclear region around ⁷⁸Ni, close to the classic shell closures with Z=28 and N=50, has attracted great attention in recent years in particular addressing the evolution of nuclear shapes. Going from the more stable to the very exotic systems a variety of phenomena are encountered, starting from the existence of shape isomerisms found in ⁶⁶Ni to coexistence of shapes, measured in the heavier systems ⁶⁸⁻⁷²Ni. The Ni isotopic chain has been investigated by the Milano gamma-spectroscopy group ex-ploiting several mechanisms, starting from sub-barrier fusion to decay, in campaigns performed in world-leading facilities. An overview of recent results in the Ni isotopic chain will be reported in this talk. (author)

[en] A new excited state at 2164 keV has been identified in ⁷²Ni with tentative spin and parity of 4⁺ based on comparison to shell model calculations. This level is suggested to be populated via the β-decay of an isomeric state in ⁷²Co, and is postulated to be one of the key states that play a role in the disappearance of isomers in ^72,74Ni. The known low-energy levels in ⁷²Ni are compared with results of shell model calculations using the NR78 interaction to follow the seniority of the observed states. In addition, the half-life of the 8⁺ isomer in ⁷⁶Ni has been measured as 630(90) ns and the full cascade of transitions from this isomer has been verified experimentally in this work. (paper)

[en] We discuss the multiple decay modes of collinear fission in "2"5"2Cf(sf, fff), with three fragments as suggested by the potential energy surface (PES). Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of "2"5"2Cf(sf) into three different masses (e.g. "1"3"2"–"1"4"0Sn, "5"2"–"4"8Ca, "6"8"–"7"2Ni), observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions) of the JINR (Dubna) the collinear cluster tripartition (CCT), is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay

[en] The neutron-rich nuclei ⁷²Ni and ⁷²Cu have been produced in the proton-induced fission of ²³⁸U at the LISOL and ISOLDE facilities of Louvain-La-Neuve and CERN. Partial β-decay schemes are presented, giving some information about the nuclear structure of their daughter nuclei ⁷²Cu and ⁷²Zn. The lifetime of ⁷²Cu was determined to be T_1/2 = 6.63(3) s, in line with previous measurements. No β-decaying isomeric states were identified in ⁷²Cu, in contrast to ⁷⁰Cu. The spin and the parity of several states in ⁷²Cu are tentatively assigned and a comparison is made with different shell-model predictions. (authors)

[en] Recent progress in experimental decay studies in the region of the doubly magic nucleus ⁷⁸Ni is discussed. In particular new data on low-energy excitations in nickel isotopes has been obtained in experiments employing fragmentation reactions. The experimental data are confronted with different shell-model calculations. The position of the 2⁺ energy levels and behavior of 8⁺ isomers in even-even ^70-76Ni isotopes has been interpreted. (orig.)