Penning-trap mass spectrometry of highly charged, neutron-rich Rb and Sr isotopes in the vicinity of A≈100

The neutron-rich mass region around A � 100 presents challenges for modeling the astrophysical r-process because of rapid shape transitions. We report on mass measurements using the TITAN Penning trap at TRIUMF-ISAC to attain more reliable theoretical predictions of r-process nucleosynthesis paths in this region. A new approach using highly charged (q = 15+) ions has been applied which considerably saves measurement time and preserves accuracy. New mass measurements of neutron-rich 94,97,98 Rb and 94,97 99 Sr have uncertainties of less than 4 keV and show deviations of up to 11� to previous measurements. An analysis using a parameterized r-process model is performed and shows that mass uncertainties for the A = 90 abundance region are eliminated.