Characterization of ³He-Implanted Gold Targets for Studying ²²Na Destruction Rates in Classical Novae

Classical novae are thermonuclear explosions on accreting white dwarf stars in binary systems. Radioactive ²²Na, a target of space based gamma-ray telescopes, is expected to be produced in considerable amounts in these novae. However, these predictions depend on the unknown destruction rate of ²²Na by protons to produce ²³Mg. The first run of a nuclear reaction experiment was performed in December 2022 at the TRIUMF-ISAC-II user facility in Canada to deduce the lifetime of a key excited state in ²³Mg. At that time, two ³He ion-implanted gold foil targets were tested and data was obtained with the Doppler Shift Lifetimes 2 setup. One target was implanted at TRIUMF and one was implanted at Lawrence Livermore National Laboratory (LLNL). Both were made using similar procedures, but produced unique signatures in the experimental data. This work focuses on the analysis of charged particles and gamma rays detected during the experiment by using data taken on each target in order to better characterize the ³He content and contamination of each target. Ongoing analysis has discovered that the LLNL target contains about twice the amount of ³He, and thus had more reactions with the ²⁴Mg beam, providing ample data on reaction rates. However, the TRIUMF target is less contaminated with elements and isotopes other than ³He and Au. Further analysis is being done to analyze the gamma spectra to discover the specific nuclides and contaminants found on each target.