Production and Separation of Radioactive Beams $^{20}$Na and $^{20}$Mg with MARS*

We studied the production and separation of $^{20}$Na and $^{20}$Mg using the MARS spectrometer at the Cyclotron Institute, TAMU. Using a $^{20}$Ne beam at 25 MeV/u on a H$_{2}$ gas target at 2 atm and 77 K, a large production of $^{20}$Na was observed. Further, we were able to study its $\beta $, $\beta \gamma $, and $\beta $-delayed $\alpha $-decay. For the $\beta $-delayed $\alpha $-decay, we observed alphas with energies 2.1, 3.8, 4.4, 4.8 MeV. Following this run, we ran a test experiment to obtain the maximum production of the rarer isotope $^{20}$Mg with the same $^{20}$Ne beam on a $^{3}$He gas target. The gas cell was filled with $^{3}$He at 1.5 atm and 77 K. Overall, the fusion-evaporation of $^{20}$Ne($^{3}$He,3n) was found to be a better reaction for $^{20}$Mg production than the fragmentation of $^{24}$Mg at 45 MeV/u previously tested with MARS. These findings will be used for planning an upcoming study of the $\beta $-delayed proton decay of $^{20}$Mg to better understand the resonance states in the $^{19}$Ne(p,$\gamma )^{20}$Na reaction of crucial astrophysical interest in studies of the hot CNO cycle in stars.