Concept of Isomer Beam Production with Heavy-Ion Storage Rings

Heavy radioactive ion beams produced by in-flight techniques often involve long-lived excited states (isomers). This presents a challenge for reaction studies because none of the existing fragment separators worldwide can resolve isomers in-flight. Here, we propose a novel scheme to produce tagged cocktail beams or pure isomer beams using an ion storage ring. The mass resolving powers of storage rings enable us to identify and separate ions of the isomeric state from the corresponding ground state in a secondary beam. For short-lived isomers, the Rare-RI Ring (R3) facility at the RI Beam Factory (RIBF) will be available, while for long-lived isomers the Experimental Storage Ring (ESR) at the GSI/FAIR facility will be utilized. Isomers often have spins and deformations significantly different from the ground states. Studying isomer structures will provide unique insight into their specific interactions, opening a new frontier in reaction studies with radioactive ion beams in the coming years.