Examination of evidence for collinear cluster tri-partition

Abstract

In a series of the experiments at different time-of-flight spectrometers of heavy ions we have observed manifestations of a new at least ternary decay channel of low excited heavy nuclei. Due to specific features of the effect, it was called collinear cluster tri-partition (CCT). The experimental results obtained initiated a number of theoretical articles dedicated to different aspects of the CCT. We compare theoretical predictions with our experimental data, only partially published so far. The model of one of the most populated CCT modes that gives rise to the so called "Ni-bump" is discussed. Detection of the 68-72Ni fission fragments with a kinetic energy E<25 MeV at the mass-separator Lohengrin is proposed for an independent experimental verification of the CCT.Comment: 16 pages, 14 figure

Additional arguments in favor of true quaternary fission of low excited actinides

“…The experimental findings and model analysis indicate that the true quaternary decay of the 252 Cf(sf) goes via very elongated prescission configurations of the mother nucleus. Similar conclusion was drawn in [7] concerning the mechanism of the collinear cluster tri-partition (CCT) of the same nucleus. Presumably the quaternary decay is due to preformation in the valley of the symmetric nuclear shapes of the potential energy surface of 252 Cf specific nuclear shape which looks like a deformed magic core (strong shell minima at N ≈ 88, 100 and Z ≈ 60) and two light clusters on the sides.…”

Manifestations of pear-shaped clusters in collinear cluster tri-partition of 252Cf

“…Later, due to the second rupture, the light cluster and the light FF become free. In general, the kinematics of the process seems to be similar to that discussed in [7].…”

“…A total yield of two Ni peaks in Ex1 does not exceed 10 −4 per binary fission which agrees with our previously obtained value. The data of Ex2 indicated that the heavy clusters in the ternary prescission configurations are predominantly magic nuclei (Table 1 in [7]). Noticeably large statistics in Ex1 allowed us to confirm previous observation.…”

True ternary fission and the rotation effect

“…Solyakin et al proposed the collinear mode of tripartition [12], when searching for TTF of 238 U by 1-GeV protons. This concept was most successfully realized in JINR experiments on FOBOS and mini-FOBOS setups [13,14,15]. All the results presented below are obtained within the framework of the "missing-mass" approach.…”