Determination of the proton separation energy of Rh93 from mass measurements

Abstract

The proposed _s13_s17957_s19p process, which occurs in the early time proton-rich neutrino winds of core-collapse supernovae, has the potential to resolve the long-standing uncertainty in the production of the light p-nuclei Mo92 and Mo94. A recent study incorporating this _s13_s17957_s19p process has indicated that the proton separation energy Sp of Rh93 is especially important in determining the relative production of these two isotopes. To reproduce the observed solar Mo92/Mo94 abundance ratio of 1.57 a Sp value for Rh93 of 1.64±0.1 MeV is required. The previously unknown masses of Ru92 and Rh93 have been measured with the Canadian Penning Trap mass spectrometer resulting in an experimental value for Sp(Rh93) of 2.007±0.009 MeV. This implies that with our current understanding of the conditions in core-collapse supernova explosions the _s13_s17957_s19p process is not solely responsible for the observed solar Mo92/Mo94 abundance ratio.