Precision Mass Measurements for the Astrophysical r process with the Canadian Penning Trap at Argonne National Laboratory

Dr. Adrian Valverde ('18)
Argonne National Laboratory

Understanding the astrophysical r-process requires nuclear data about neutron-rich nuclei far from the valley of stability; key among these data are nuclear masses. The Canadian Penning Trap mass spectrometer (CPT) at Argonne National Laboratory measures such masses using the state-of-the-art phase-imaging ion-cyclotron-resonance technique. It is currently located at the CARIBU facility of Argonne’s ATLAS accelerator, where it has measured masses of interest to the formation of the rare-earth peak in the r -process abundance pattern produced from the fission of CARIBU’s Californium-252 source. The next step in r -process studies for the CPT will be the measurement of masses of interest for the formation of the heaviest A ∼ 195 r -process abundance peak. Traditional particle-fragmentation, target-fragmentation, or fission production techniques will not efficiently produce these nuclei. Multi-nucleon transfer (MNT) reactions between two heavy ions, however, can produce these nuclei effectively. The N = 126 Factory currently under construction at ATLAS will use MNT reactions to produce such nuclei and deliver them to the CPT for mass measurements or to other experimental systems.

This work is supported in part by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357; by NSERC (Canada), Application No. SAPPJ-2018- 00028; and with resources of ANL’s ATLAS facility, an Office of Science User Facility.

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