Using neutron and gamma-ray spectroscopy, researchers from institutions including FRIB, the University of Tennessee, Knoxville; Lawrence Livermore National Laboratory; Oak Ridge National Laboratory; and Los Alamos National Laboratory collaborated to study the beta decay of oxygen-24 and measure its beta-delayed neutron energy spectrum for the first time. The results showed three strongly populated, isolated states in the transition from oxygen-24 to fluorine-24, which allowed researchers to extract the decay strength in fluorine-24 up to 6.2 million electron-volt (MeV). The team published its findings in Physical Review C (“First beta-delayed neutron spectroscopy of oxygen-24”).

The researchers compared the experimental results with nuclear theories such as the empirical shell model and advanced ab initio calculations. In the transition from oxygen-24 to fluorine-24, some shell calculations correctly predicted the structure of both nuclei without needing to change their structure with a stronger proton-neutron force. However, while some advanced ab initio calculations reproduced the structure of fluorine-24 around its ground state, there were discrepancies for the neutron unbound states.

According to the authors, “This implies that predicting the decay properties of the neutron-rich nucleus is not trivial, and optimizations are still required. A more complete description of the experimental finding and a better understanding of the underlying effects of nuclear structure await further theoretical developments.” 

This material is based upon work supported by the U.S. Department of Energy, Office of Science and Office of Nuclear Physics and was sponsored in part by the National Science Foundation and the National Nuclear Security Administration. 

Michigan State University (MSU) operates the Facility for Rare Isotope Beams (FRIB) as a user facility for the U.S. Department of Energy Office of Science (DOE-SC), with financial support from and furthering the mission of the DOE-SC Office of Nuclear Physics.