E23076: an ISOL-type study of neutron-rich cobalt isotopes at the FDSi

In April of 2025, an experiment was performed with the FDSi to study the decay of neutron-rich cobalt isotopes ^68-71Co. The experiment was the first to operate in a new mode of the FDSi that makes simultaneous use of its two focal planes for combined high-resolution and high-efficiency spectroscopy. This new mode of operation enabled experiments at a high rate, but required a relatively isotopically pure beam. The FRIB primary beam was pulsed to produce a grow-in and decay-out cycle, allowing us to distinguish between short- and long-lived isomeric states of the implanted ions and their decay products. This new FDSi mode opens up the possibility to perform “ISOL-type” experiments at FRIB, which can produce rare isotopes that are not easily accessible to ISOL facilities. The details of this experimental setup are presented, along with some preliminary results for the ⁷⁰Co decay studied in e23076.