The ORNL Analysis Technique for Extracting ${\hat{I}}^2$-Delayed Multi-Neutron Branching Ratios with BRIKEN

Abstract

Many choices are available in order to evaluate large radioactive decay networks. %multi-particle decay data. There are many parameters that influence the calculated ${\hat{I}}^2$-decay delayed single and multi-neutron emission branching fractions. We describe assumptions about the decay model, background, and other parameters and their influence on ${\hat{I}}^2$-decay delayed multi-neutron emission analysis. An analysis technique, the ORNL BRIKEN analysis procedure, for determining ${\hat{I}}^2$-delayed multi-neutron branching ratios in ${\hat{I}}^2$-neutron precursors produced by means of heavy-ion fragmentation is presented. The technique is based on estimating the initial activities of zero, one, and two neutrons occurring in coincidence with an ion-implant and ${\hat{I}}^2$ trigger. The technique allows one to extract ${\hat{I}}^2$-delayed multi-neutron decay branching ratios measured with the hybrid \textsuperscript{3}He BRIKEN neutron counter. As an example, two analyses of the ${\hat{I}}^2$-neutron emitter \textsuperscript{77}Cu based on different {\it a priori} assumptions are presented along with comparisons to literature values.

21 pages, 10 figures