FIRST MEASUREMENT OF HALF-LIVES OF r-PROCESS Zn AND Ga ISOTOPES

摘要

The P-decays of neutron-rich nuclei near the doubly magic ~(78)Ni were studied at the Holifield Radioactive Ion Beam Facility (HRIBF) using an electromagnetic isobar separator. The half-lives of ~(82)Zn (228±10 ms), ~(83)Zn (117±20 ms) and ~(85)Ga (93±7 ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations [1]. The experimentally measured values were applied to validate a new Density Functional used for half-life calculations. It was observed that in the region of interest of this work, half-lives are very sensitive to the ordering of proton single particle states. A sample rapid neutron capture nucleosynthesis calculation using our new set of measured and calculated half-lives shows a significant redistribution of isobaric abundances and a strengthened yield of A>140 nuclei.