Technique and study of $\beta $-delayed p-decay of proton-rich nuclei

We developed a technique to measure beta-delayed proton-decay of proton-rich nuclei produced and separated with the MARS recoil separator at TAMU. In particular we studied the case of $^{23}$Al produced in inverse kinematics. Its $\beta $-decay was studied before, using $\beta -\gamma $ coincidence techniques. The states populated in $^{23}$Mg above the proton threshold at S$_{p}$=7580 keV may proton decay. They are resonances in the proton capture reaction $^{22}$Na(p,$\gamma )^{23}$Mg, crucially important for the depletion of $^{22}$Na in ONe novae. A setup consisting of a thin Si strip detector (p-detector) and a thick Si detector ($\beta $-detector) was designed. A HpGe detector outside the chamber detected $\gamma $-rays. A rotating energy-degrader was used to implant the source nuclei (from 40 MeV/u) in the middle of the thin p-detector. We have pulsed the beam from the cyclotron, implanted the source, then measured $\beta -$p and $\beta -\gamma $ coincidences off-beam. The technique has shown a remarkable selectivity to $\beta $-delayed charged particle emission and would work even at radioactive beam rates of a few pps.