β-Delayed Proton Decays Near the Proton Drip Line

Abstract：

The experimental study on β-delayed proton decays near the proton drip line published by our group over the last 8 years were reviewed and summarized briefly,including first observation of 9 precursors in the rare-earth region and new measurements of 5 nuclei in the mass-90 region near N=Z line with the aid of the “p-γ” coincidence in combination with a He-jet tape transport system.Systematically comparing the experimental data with the current nuclear-model predictions, following points were represented. (1) the experimental half-lives for ⁸⁵Mo and ⁹²Rh as well as the predicted “waiting point”nuclei ⁸⁹Ru and ⁹³Pd are 5—10 times longer than the macroscopic-microscopic model predictions given by Moller et al [At. Data Nucl Data Tables, 66, 131(1997)]. It considerably influences the prediction of mass abundances of the nuclides produced in rp-process. (2) The current-model predictions are not consistent with the experimental spin-parity assignments of the proton drip-line nuclei ¹⁴²Ho and ¹²⁸Pm. However, the nuclear potential energy surface (PES) calculated by using a Woods-Saxon-Strutinsky method reproduced the experimental results. (3) The Alice code overestimated the production reaction cross sections of the studied 9 rare-earth nuclei by one order of magnitude or two, while HIVAP code overestimated them by one order of magnitude approximately.