Precision isochronous mass measurements at the storage ring CSRe in Lanzhou

Direct mass measurements of 78Kr projectile fragments have been performed in the recently commissioned storage ring CSRe employing the isochronous mass spectrometry method. A new data-analysis technique has been developed to correct the drifts in the revolution frequencies caused by instabilities of the magnetic fields in the CSRe, thus yielding a mass resolving power of R=m/Δm≈1.7×105R=m/Δm≈1.7×105 (sigma). Masses for 45V, 47Cr, 49Mn and 51Fe nuclei are determined with a relative mass precision of δm/m≈2×10−7δm/m≈2×10−7 (sigma) which is an improvement by a factor of ∼2∼2 compared to the literature values.