Delayed 160Tb radioactivity buildup due to 159Tb(n,2n) nuclear reaction products transformation and subsequent fusion

This paper deals with the formation of a bound dineutron in the outgoing channel of the 159Tb(n,2n)158gTb nuclear reaction followed by assumed transformations of the reaction products 158gTb and 2n. Such nuclear processes were studied in detail from the point of view of 160Tb/160Dy/160Ho amount of nuclei versus time dependence. Some signs of fusion process between heavier nuclei (158Tb and/or 158Gd) and the deuteron, that is a bound dineutron decay product, were detected as unexpected increas-ing of 879.38 keV gamma-ray peak count rate due to 160Dy gamma-transitions. The mathematical model, including three systems of differential equations, was developed to describe the experimental data. This development requires a reasonable estimate of the half-life of a bound dineutron, which was found to be equal 5,877 s as an upper limit. We mathematically modeled the experimentally observed delayed in time build-up of the 160Tb radioactivity with a maximum at about 495 d since the neutron irradiation completion of the Tb sample, based on the similarity with the parent-daughter nuclei radioactivity decay and nuclear accumulation processes.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).