New Developments for Isochronous Mass Measurements of Short‐Lived Nuclei

The combination of the in‐flight separator FRS and the storage‐ring ESR at GSI offers unique possibilities for high accuracy mass and lifetime measurements of bare and few‐electron fragments. Operating the ESR in the isochronous mode allows for measurements of revolution frequencies of stored ions without cooling. Isochronous Mass Spectrometry (IMS) can be applied to fragments with half‐lives as short as several tens of microseconds. Newly developed magnetic rigidity tagging increases the resolving power of IMS to about 500000. IMS can be used to measure masses of nuclei with rates even lower than one ion per day, a property also needed for the purpose of the ILIMA project at the future facility FAIR.