[en] The search for the beta-delayed fission in neutron-rich nuclei has been performed at the IRIS mass-separator. The delayed fission has not been observed: The limits of probabilities for 228, 230, 232 Fr and 232 Ac precursors have been obtained. The new isotopes 232 Fr, 233, 234 Ra have been identified. (orig.)

[en] Measurements were made to determine the longitudinal electron polarization of the β^--decays of Ca-45, Pm-147 and Tl-204. The β^--transition of Co-60 served as a reference standard and all measurements were carried out relative to it thus strongly reducing the instrumental errors. The measuring principle is based on Mott-scattering technique with a Mott analyzer similar to that of van Klinken and a Wien-filter for spin transformation from longitudinal to transverse. For each isotope several measurements were carried out at different electron energies ranging from 80-200 keV. In summary, not a single deviation from the theoretical value of -v/c was found. (orig.)

[en] The two presently available measurements of the low-energy ³H(α, γ)⁷Li reaction differ from each other by roughly 30% in total magnitude as well as in their determination of the branching ratios for the transition into the two final ⁷Li bound states. Studying the ³H(α, γ)⁷Li reaction in the framework of the microscopic Resonating Group Method we were able to reproduce both experimental total cross sections using different effective nucleon-nucleon interactions. However, none of the effective forces yields branching ratios compatible with the data measured by the Toronto-Muenster-collaboration. (orig.)

[en] A Pb target was bombarded with ¹²C nuclei of an energy of 15 and 43 GeV. The target was periodically transported to the inside of the neutron multiplicity detector which allowed measuring time distributions for events of multiple emission of delayed neutrons. Abnormal neutron emitters have not been found. Upper limits of probabilities of their production were estimated for the half-life range 10-10⁵ s and for different mean multiplicities of neutrons anti n. The values obtained are within the interval from 1.4.10^-9 (for anti n = 12) to 4.10^-6 (for anti n = 2). (orig.)

[en] Integral fission cross sections in the system ²³⁸U+²³⁸U were measured at beam energies below the interaction barrier V_C. Scattering angle dependent probabilities and integral cross sections for Coulomb fission were calculated. It is concluded that earlier observed discrepancies between measured and calculated angular distributions for the one-neutron transfer product ²³⁹U cannot be explained by sequential fission. Multi-nucleon transfer induced fission is observed down to energies (0.90±0.02) x V_C. (orig.)

[en] We show that the dinotor is sensitive to discrete energy level corrections to the continuum approximation for the density of states. These corrections do not destroy the metastability of the dinotor, but may produce a 'magnetic number' effect. New metastable configurations of the dinotor may also exist, possibly creating further difficulty identifying the dinotor as the cause of the anomalon effect. (orig.)

[en] Recent cranked shell model calculations give a possible explanation for the occurrence of two S-bands in Ba-nuclei. (orig.)

[en] We report on the first in-beam study of high spin levels in ⁸³Y which were established up to 9.0 MeV excitation energy and probable spin of 41/2⁺ resp. 27/2^- by means of the reaction ⁵⁸Ni(²⁸Si, 3p). Ten lifetimes and six lifetime limits in the 10^-12-10^-9 s range were determined in two recoil distance Doppler shift experiments. The positive parity yrast states form a g_9/2 Coriolis decoupled band with partial alignment, near-rigid rotor moment of inertia and deformation β₂ = 0.29. The negative parity yrast band has very similar collective properties; it shows a pronounced band crossing at rotational frequency ℎω ≅ 0.40 MeV which we associate with twoquasiparticle g_9/2 proton alignment. At 2.56 MeV excitation, a second ΔI = 1 band starting with 17/2^- was found. On the basis of the similarity to ⁸⁵Y and the very weak E2 decay of this state, we suggest that this band has (3qp) configuration with an aligned g_9/2 neutron pair. The lifetimes of the lowest 2⁺ and 4⁺ state in ⁸⁴Zr populated in the reaction ⁵⁸Ni (²⁸Si, 2p) were determined to be τ(2) = 17.8(11) ps resp. τ(4) = 3.5(4)ps. (orig.)

[en] We deduce that the total energy transfer associated with the narrow positron lines observed in heavy-ion collisions is given approximately by the sum of the rest masses of the positron and the accompanied electron plus their kinetic energies. Since the same behaviour has been established previously for the production process of the dynamically induced positrons, our observation represents a strong hint that the origin of the e⁺-lines may also be connected with the strong Coulomb field occuring in heavy-ion collisions. (orig./HSI)

[en] In impulse approximation the calculated cross section of the reaction d+p → p+p+n at 9 GeV/c depends strongly on the spectator momentum distribution used. We compare the results of a conventional calculation to those of light-cone dynamics and propose to decide between the two approaches by measuring the angular distribution of the low-momentum recoil proton in coincidence with a high-momentum proton. (orig.)