[en] Investigation of the ²³⁵U(n_th, f) reaction using the miniFOBOS double-arm time-of-flight spectrometer of fission fragments confirmed manifestations of the earlier unknown many-body, at least ternary, decay involving almost collinear decay-product escape, which were first observed in the spontaneous fission of ²⁵²Cf(sf). The use of variables sensitive to the nuclear charge of fission fragments allowed the reliability of identification of decay events to be increased and new decay modes to be revealed.

[en] In our previous publications we discussed possible physical scenario standing behind rectangular–like structures in the fission fragments mass-correlation distributions from ²⁵²Cf(sf). The rectangle is bounded by the known magic nuclei such as ⁶⁸Ni, ⁸⁴Se and others. The fission events aggregated in the rectangle show extremely low total kinetic energies. Previously only decay mode with two Ni clusters in the exit channel was discussed. A more complete analysis is presented which gives additional arguments in favour of true quaternary fission of ²⁵²Cf (sf). (paper)

[en] Results: of the first direct observation of the true ternary fission of ²³⁴Pa* nucleus are presented. The yield of the effect depending on the experimental geometry is about 10^-5/binary fission. Mass of the lightest fragment in the triplet lies mainly in the range of 20–40 a.m.u. An intimate connection between the effect and known cluster decay as well as conventional binary fission is briefly discussed.

[en] The manifestation of a new original effect appearing at crossing of the metal foils by fission fragments is reported. The effect takes place predominantly at front impacts. The obtained results suggest that a fragment from conventional binary fission is borne in shape-isomer state which looks like a di-nuclear system with magic core. (paper)

[en] We discuss the manifestations of a new original effect appeared at crossing of the metal foils by fission fragments. We have observed significant mass deficit in the total mass M_s of the fission fragments detected in coincidence with ions knocked out from the foil. It was shown that at the large angles of scattering of the knocked–out ions from the foil predominantly conventional elastic Rutherford scattering takes place. As the result M_s corresponds to the mean mass of the mother system after emission of fission neutrons (no missing mass). In contrast, in near frontal impacts fission fragment misses essential part of its mass. Residual nuclei at least for the fragments from the heavy mass peak show magic nucleon composition. (paper)

[en] Careful studies of the fission fragments mass correlation distributions let us to reveal specific linear structures in the region of a big missing mass. It became possible due to applying of effective cleaning of this region from the background linked with scattered fragments. One of the most pronounced structure looks like a rectangle bounded by the magic nuclei. The fission events aggregated in the rectangle show a very low total kinetic energy. We propose possible scenario of forming and decay of the multi-cluster prescission configuration decisive for the experimental findings. This approach is valid as well for treating of another rare decay modes discovered in the past. (paper)

[en] A new off-line timing method for PIN diode signals is presented which allows the plasma delay effect to be suppressed. Velocities of heavy ions measured by the new method are in good agreement within a wide range of masses and energies with velocities measured by time stamp detectors based on microchannel plates.

[en] Basic experimental results confirming the existence a new cluster-decay type called collinear cluster tripartition (CCT) are presented. Decays of this type manifest themselves, in particular, as a two-dimensional region of a locally enhanced yield of fragments (bump) that corresponds to specific missing-mass values in the mass-mass distribution of fission fragments. One of the decay modes that contribute to the bump can be treated as a cluster-decay type that is new in relation to the well-known heavy-ion or lead radioactivity. The conclusions drawn from an analysis of correlation mass distributions are confirmed by the results obtained from neutron-gated data, measurements of the nuclear charge for CCT events, and the direct detection of new-decay products

[en] We discuss the quality of heavy ions (HI) mass reconstruction in the wide range of HI energies and masses using Si PIN diodes for measuring both energy and time-of-flight. The results are based on the experimental data obtained at the IC-100 accelerator in the Flerov Laboratory of the JINR (Dubna, Russia). (paper)