Empirical description of beta-delayed fission partial half-lives

TL;DR

This paper investigates the systematic behavior of beta-delayed fission partial half-lives, revealing an exponential dependence on the difference between beta decay Q-values and fission barriers, confirmed across various models and extensive data.

Contribution

It introduces a semi-phenomenological framework to describe bDF partial half-lives and identifies a universal exponential trend based on nuclear energy differences.

Findings

bDF partial half-lives exponentially depend on Q value minus fission barrier

The trend holds over 7 orders of magnitude in experimental data

The dependence is consistent across different fission barrier models

Abstract

Background: The process of beta-delayed fission (bDF) provides a versatile tool to study low-energy fission in nuclei far away from the beta-stability line, especially for nuclei which do not fission spontaneously. Purpose: The aim of this paper is to investigate systematic trends in bDF partial half-lives. Method: A semi-phenomenological framework was developed to systematically account for the behavior of bDF partial half-lives. Results: The bDF partial half-life appears to exponentially depend on the difference between the Q value for beta decay of the parent nucleus and the fission-barrier energy of the daughter (after beta decay) product. Such dependence was found to arise naturally from some simple theoretical considerations. Conclusions: This systematic trend was confirmed for experimental bDF partial half-lives spanning over 7 orders of magnitudes when using fission barriers calculated from either the Thomas-Fermi or the liquid-drop fission model. The same dependence was also observed, although less pronounced, when comparing to fission barriers from the finite-range liquid-drop model or the Thomas-Fermi plus Strutinsky Integral method.