[en] The experimental studies of the energy dependence of the delayed neutron parameters for various fissioning systems has shown that the behavior of a some combination of delayed neutron parameters (group relative abundances a_i and half lives T_i) has a similar features. On the basis of this findings the systematics of delayed neutron experimental data for thorium, uranium, plutonium and americium isotopes have been investigated with the purpose to find a correlation of DN parameters with characteristics of fissioning system as well as a correlation between the delayed neutron parameters themselves. Below we will present the preliminary results which were obtained during this study omitting the physics interpretation of the results. (author)

[en] Spontaneous fission is a phenomenon exhibited by heavy nuclei, which can be a major mode of decay of nuclei of elements heavier than thorium and can be a determining factor in their stability. For purposes of this paper, spontaneous fission will be considered a process in which a nucleus breaks up into two approximately equal parts. The emission of light nuclei or heavy ions such as ¹²C, ¹⁶O, or ³²S will not be considered. This radioactive decay mode is often much smaller than the spontaneous fission decay mode, although this is not true in all cases. Barwick noted that this might indicate that the assumed half-life for spontaneous fission of some older experiments might be partially due to heavy fragment radioactivity. Other than taking note of this potential correction to spontaneous fission half-lives, this decay mode of heavy fragment radioactivity will be ignored. Excited states of some heavy nuclei may decay via spontaneous fission. These so-called fission isomers will not be discussed here. Electron capture (EC) or beta-delayed fission is a process in which prompt fission of a sufficiently excited daughter state occurs following population by EC or beta decay. The fission activity will appear to decay with the half-life of the parent and was earlier confused in some cases with SF. This process has been discussed in detail in a review and will not be considered in this paper

No abstract available

No abstract available

No abstract available

No abstract available

No abstract available

[en] An analysis of selected fission fragment angular distributions of various target is made using exact theoretical expressions. Theoretical anisotropies obtained from the transition state model are compared with their corresponding values deduced from the statistical scission model. The nuclear moment of inertia extracted from the model calculations are compared with their estimated values from a microscopic theory, which includes the nuclear pairing interaction. Single particle levels of Nilsson et al. are utilized. It is found that the value of the statistical parameter is very sensitive to the energy gap parameter, Δ. The reduction of energy gap results in an increase in the moment of inertia. The effect of pairing interaction on the inertia parameters are illustrated and discussed

[en] The cumulative fission yields for 45 fission product nuclides of ²³⁸U fission induced by neutron of fast reactor spectrum and high energy (around 14.0 MeV) neutron have been evaluated. The results were compared with the ENDF/B-6, JENDL-3/FY, CENDL-FY (86) and JEF-2/FY. It was found that in the total 68 evaluated values, the most of present results (88 percent in total) are in agreement with at least one of the main fission yield libraries within the quoted error limits

[en] Projectile fragmentation and fission, induced in collisions of ²³⁸U at 1 A GeV with lead, have systematically been studied. A complete survey on the isotopic production cross sections of all elements between vanadium (Z = 23) and rhenium (Z = 75) down to a cross section of 0.1 mb is given. About 600 isotopes produced in fragmentation and about 600 isotopes produced in fission were identified in the GSI fragment separator FRS from magnetic rigidities, time-of-flight values, and the energy loss in an ionisation chamber. In addition, the velocity distributions of all these reaction products have been mapped, and the products are unambiguously attributed to the different reaction mechanisms due to their kinematical properties. The results are compared with empirical systematics and previous data. The velocity of the fragments obtained in the fission process by the Coulomb repulsion allows to reconstruct the TKE-value of the break-up and to identify the atomic number of the fissioning nucleus in hot fission. The mean velocities of light projectile fragments were found to be higher than the beam velocity. (orig.)