- Editors' Suggestion
Neutron fluence and relation of yields for transuranium nuclei during nucleosynthesis under conditions of thermonuclear explosions
Phys. Rev. C 114, 044603 – Published 1 October, 2026
DOI: https://doi.org/10.1103/k5hb-rpp1
Abstract
Background: Activation of actinide targets in pulsed neutron fluxes of thermonuclear explosions is similar to cosmological nucleosynthesis and allows the synthesis (by multiple captures) of highly neutron-rich transuranium nuclei, many of which are extremely poorly studied. The key parameter of nucleosynthesis efficiency is the neutron fluence, estimated in calculations based on the adequacy of reproducible isotope yields. Model estimates lead to significant differences in the fluence values.
Purpose: A sensitive functional is needed that, like an indicator, would provide additional information about the achieved fluence.
Method: An indication of neutron fluence can be derived from an analysis of the yield relations for transuranium nuclei. Modeling of the creation of transuranium nuclei was performed on the basis of the developed dynamic adiabatic binary model for seven large-scale U.S. experiments: Mike, Anacostia, Par, Barbel, Vulcan, Kankakee, and Сyclamen.
Results: Along with the target declared in the experiments, a starting uranium-plutonium mixture (which occurs in the first stage of combustion) has been proposed as an alternative. It has been analytically derived that under static conditions for starting isotopes and the dependence of isotopic relations (for pairs of adjacent isotopes) on fluence can be roughly approximated by a linear function in the range of achieved fluxes. Modeling with the introduction of process dynamics confirmed the hypothesis of a roughly linear dependence of isotopic relations on fluence. Calculations showed numerical agreement between the isotopic relations and experiments in the scenario with a large injection into the nucleosynthesis process. This scenario significantly corrects the explosive accumulation of transuranium nuclei.
Conclusions: The obtained dependence of the isotope relation on fluence confirmed that the isotope relation (for mass numbers and 245) can be considered a practically significant function, sensitive to the achieved fluence.
