Mass Measurements for the Astrophysical R-Process and Commissioning of the N=126 Factory*

The rapid neutron capture process (r-process) is responsible for nucleosynthesis of half of the isotopes above iron. This occurs far from stability, passing through isotopes with short half-lives. To better understand the r-process more nuclear data in this region is needed. Part of this effort is precise mass measurements accomplished with the Canadian Penning Trap (CPT) at Argonne National Laboratory’s ATLAS facility. Using the Phase Imaging Ion Cyclotron Resonance technique, the cyclotron frequency of a trapped ion can be measured and the precise mass determined. CPT results in the rare earth peak will be presented. The heaviest r-process peak occurs at N=126. It is difficult to produce isotopes in this region with traditional techniques so the N=126 Factory at ATLAS will use multinucleon transfer (MNT) reactions to produce these isotopes that will be transferred to the CPT for mass measurements. This is done by a heavy ion beam interacting with a platinum target creating neutron rich isotopes. Products are collected in an RF (radiofrequency) gas catcher and extracted with an RF quadrupole guide before mass separation, bunching, and delivery to the CPT and other experiments. Reaction products from the gas catcher have successfully been extracted.