Speaker
Description
Nuclear reactions frequently involve radioactive species as one or both components in explosive astrophysical scenarios, such as (super)novae, Type I X-ray bursts, and neutron star mergers. The reaction rates involved in calculating the astronomical observables are frequently unknown or poorly constrained in the Gamow window, requiring both direct and indirect measurements with both stable and rare isotope beams. The Facility for Rare Isotope Beams (FRIB) is a new, cutting edge accelerator complex hosted at Michigan State University. FRIB is designed to meet user needs, providing some of the most intense rare isotope beams to experimentalists from around the globe. Most of the rare beams are produced onsite using the Advanced Rare Isotope Separator (ARIS) either via projectile fragmentation or in-flight fission. ARIS produces unique beams for each experiment, including tailor-made intensity, purity, and energy suited to the users' requests up to our present capabilities. The FRIB linac presently produces beams up to 20 kW, and we recently successfully performed tests at 30 kW, with the final goal of 400 kW. The primary beam energies are typically in the 100-300 MeV/u range and impinge on mm-thick, rotating graphite target. FRIB has a large, growing list of primary beams available to support new requests for intense secondary beams, which can be utilized in indirect measurements at energies above the Gamow window, or the species from ARIS can be stopped and re-accelerated for direct measurements. The presentation will focus on how the ARIS team calculates, produces, and quantifies rare isotope beams for nuclear astrophysics experiments.