High precision mass measurements for the astrophysical r-process

The production of isotopes via the rapid neutron capture process depends sensitively on the atomic mass of the nuclides involved. In light of the recent observation and confirmation of neutron-star mergers as being one of the sites of the r-process, new nuclear data for improved abundance calculations are more urgently needed. To this end, the development of new radioactive ion beam facilities and measurement techniques now extends our reach into unexplored territories. One such facility is the N = 126 beam factory at Argonne National Laboratory. An essential component of this facility will be a multi-reflection time-of-flight mass spectrometer, currently being commissioned at the University of Notre Dame. Mass resolving power of 60,000 using K-39(+) ions has been achieved. Simulation and continued optimization are underway to improve the efficiency of the device.