[en] This conference is dedicated to the last achievements in experimental and theoretical aspects of the nuclear fission process. The topics include: mass, charge and energy distribution, dynamical aspect of the fission process, nuclear data evaluation, quasi-fission and fission lifetime in super heavy elements, fission fragment spectroscopy, cross-section and fission barrier, and neutron and gamma emission. This document gathers the program of the conference and the slides of the presentations

[en] Besides fission into two or three fragments, a heavy or superheavy nucleus spontaneously breaks into four, five or six nuclei, of which two are asymmetric or symmetric heavy fragments and the others are light clusters. Examples are presented for the cold fission of ²⁵²Cf, in which the emitted clusters are: 2α, α + ¹⁰Be, 3α, α + ⁶He + ¹⁰Be and 4α. A comparison is made with the recently observed ²⁵²Cf cold binary fission and cold ternary (accompanied by an α particle or by ¹⁰Be cluster) fission. The strong shell effect associated with the doubly magic heavy fragment ¹³²Sn is emphasized. From the analysis of different configurations of fragments we conclude that the most favourable mechanism in such a decay mode should be cluster emission from an elongated neck formed between the two heavy fragments. (author). Letter-to-the-editor

[en] The following topics were dealt with: Macroscopic and microscopic approaches to fission, the double fission barrier, the scission point, nuclear reactions induced by neutrons

[en] The contents and the documentation of the ENDF/B-6 fission-product yield sublibraries which were released in 1991 and updated in 1993 and 1995, are summarized. Copies of the data libraries are available on magnetic tape or PC diskettes from the IAEA Nuclear Data Section, costfree upon request. (author)

[en] It is shown that the existing data for the different fissioning nuclei on the proton odd-even effect δ_p, conditional charge variance (σ_Z²(Z:A)) and the light-charged-particle accompanied ternary fission-to-binary fission ratio T/B, can be treated in a coherent way to understand the nature of dynamics that comes into play during the last stages of the fission process through the rupture of the neck joining the nascent fission fragments. (author)

[en] Cold fragmentation is a limiting case of nuclear fission, where the fragments carry no excitation energy and hence all of the available energy is converted into the total kinetic energy of the primary fragments. It is argued that cold fragmentation corresponds to the most compact configuration being compatible with energy conservation. Experimental results and methods for thermal neutron induced and spontaneous fission are reviewed. Characteristic experimental features of cold fragmentation are discussed in terms of a static scission point model. While these features may be interpreted on rather simple physical grounds, it is pointed out that the mere fact of cold fragmentation being observable at all is a challenge to any theory of nuclear fission

[en] After an outline of the experiments which led to the discovery of nuclear fission by O. Hahn and F. Strassmann in December 1938, the present state of knowlege of the fission process is reviewed. Important aspects of this process such as the double-humped shape of the fission barrier have been recognized only during the last decade. Other aspects such as the behavior of the fissioning nucleus between saddle point and scission point and the asymmetry of the mass division are not yet fully understood. In addition to further experimental and theoretical studies of the fission process itself, work on nuclear reactions between heavy nuclei may lead to better insights since these reactions, like the fission process, reveal the dynamical behaviour of nuclear matter. (orig.)

[en] This conference report gives a summary of the talks on the international symposium about physics and chemistry of fission held in Juelich in 1979. The main topics dealt with were potential energy surfaces, spectroscopy of highly deformed shapes, saddle-to-scission stage in fission and heavy-ion fission

[en] We develop a model for pair-breaking in order to explain the behavior of the even-odd effects displayed both by the fragment yields and the fragments' kinetic energies in low energy nuclear fission. Neutron and proton pair breaking are taken into account. Two pair-breaking mechanisms are considered. In the first, pairs are broken at the saddle point and the individual members of the broken pairs are assumed to localise independently in the fragments. In the second, pairs are broken at scission and individual members of the broken pairs are assumed to end in different fission fragments. With this simple model all existing experimental data can be explained, including results of cold-fragmentation. (orig.)

No abstract available