SCHOTTKY MASS-SPECTROMETRY AT THE HEAVY-ION STORAGE-RING ESR

Schottky mass spectrometry is a novel method of precision nuclear mass spectrometry based on the measurement of the revolution frequencies o f cooled ions in storage rings performed by non-destructive frequency analysis of the beam noise, the well-established Schottky diagnosis te chnique. The method was applied for the first time at the Experimental Storage Ring ESR at GSI observing electron cooled highly charged ions up to bare nuclei at relativistic energies around several hundred MeV /u. To demonstrate the performance and feasibility of the method at th e ESR, experimental tests have been carried out using beams of nuclear fragments produced in the ring itself by the interaction of different primary beams with the internal gas jet target. Futhermore, first Sch ottky mass measurements of secondary nuclear beams produced by project ile fragmentation of Au and Bi primary beams in a thick Be-target were carried out in order to determine the masses for numerous heavy neutr on deficient nuclei which had not been measured before. Relative accur acies for the measured mass values in the order of 1 x 10(-6) and belo w can be achieved. The method is briefly discussed and some early resu lts are presented.