  The Canadian Penning Trap mass spectrometer has made mass measurements of 33
neutron-rich nuclides provided by the new Californium Rare Isotope Breeder
Upgrade (CARIBU) facility at Argonne National Laboratory. The studied region
includes the 132Sn double shell closure and ranges in Z from In to Cs, with Sn
isotopes measured out to A = 135, and the typical measurement precision is at
the 100 ppb level or better. The region encompasses a possible major waiting
point of the astrophysical r process, and the impact of the masses on the r
process is shown through a series of simulations. These first-ever simulations
with direct mass information on this waiting point show significant increases
in waiting time at Sn and Sb in comparison with commonly used mass models,
demonstrating the inadequacy of existing models for accurate r-process
calculations.
