Beta-delayed fission in the coupled Quasi-particle Random Phase Approximation plus Hauser-Feshbach approach

Abstract

Beta-delayed neutron emission and $β$-delayed fission ($β$df) probabilities were calculated for heavy, neutron-rich nuclei using the Los Alamos coupled Quasi-Particle Random Phase Approximation plus Hauser-Feshbach (QRPA+HF) approach. In this model, the compound nucleus is initially populated by $β$-decay and is followed through subsequent statistical decays taking into account competition between neutrons, $γ$-rays and fission. The primary output of these calculations includes branching ratios along with neutron and $γ$-ray spectra. We find a relatively large region of heavy nuclides where the probability of $β$df is near 100%. For a subset of nuclei near the neutron dripline, delayed neutron emission and the probability to fission are both large which leads to the possibility of multi-chance $β$df (mc-$β$df). We comment on prospective neutron-rich nuclei that could be probed by future experimental campaigns and provide a full table of branching ratios in ASCII format in the supplemental material for use in various applications.