Production and $β$ decay of rp-process nuclei $^{96}$Cd, $^{98}$In and $^{100}$Sn

Abstract

The $β$-decay properties of the N=Z nuclei $^{96}$Cd, $^{98}$In and $^{100}$Sn have been studied. These nuclei were produced at the National Superconducting Cyclotron Laboratory (NSCL) by fragmenting a 120 MeV/nucleon $^{112}$Sn primary beam on a Be target. The resulting radioactive beam was filtered in the A1900 and the newly commissioned Radio Frequency Fragment Separator (RFFS) to achieve a purity level suitable for decay studies. The observed production cross sections of these nuclei are lower than predicted by factors of 10 to 30. The $^{100}$Sn production cross section is 0.25(15) pb, in sharp contrast with the 120 pb lower limit established at 63 MeV/nucleon incident energy of the same primary beam. The deduced half-life of $^{100}$Sn is 0.55$^{+0.70}_{-0.31}$ s, in agreement with previous measurements. Two $β$-decaying states in $^{98}$In were observed with measured half-lives of 47(13) ms and 0.66(40) s. The half-life of $^{96}$Cd, which was the last experimentally unknown waiting point half-life of the astrophysical rp-process, is 1.03$^{+0.24}_{-0.21}$ s. The implications of the experimental T$_{1/2}$ value of $^{96}$Cd on the abundances predicted by rp-process calculations and the origin of A=96 isobars such as $^{96}$Ru are explored.