Novel isochronous features for FRS-ESR experiments with stored exotic projectile fragments

Abstract

High-resolution experiments with stored and cooled exotic nuclei have been pioneered and applied with the FRS-ESR facilities at GSI since 1991. Exotic nuclei have been produced, spatially separated in flight with the FRS and injected in the longitudinal dispersive storage ring ESR for high-resolution mass and lifetime measurements. For very short-lived nuclei, i.e., with lifetimes shorter than the cooling time, the ion-optical system of the ring has to be operated in the so-called isochronous mode. Under this condition, the inherent momentum spread of the fragments does not limit the accuracy of experiments if both the revolution time and the magnetic rigidity are simultaneously measured for the circulating ions. In this contribution, we demonstrate a novel feature for the ESR operated in the isochronous mode and the phase-space matching of FRS and ESR.