SCHOTTKY MASS-SPECTROMETRY AT THE EXPERIMENTAL STORAGE-RING ESR

The application of Schottky beam diagnosis [1] for measurements of nuclear masses was proposed nearly 10 years ago when injection and electron cooling of radioactive beams in the Experimental Storage Ring ESR came into consideration [3]. Experimental tests of this novel method have been performed recently using electron cooled beams of nuclear fragments produced in the ring itself by the interaction between different primary beams and the internal gas jet target. Both the relative accuracy and the resolution of mass differences in Schottky spectra proved to be in the low, 1 x 10(-6) range, allowing even the resolution of isomeric from ground state masses in some cases. Because of the required cooling time the spectrometry is applicable, so far, to nuclei with life times of at least a few seconds.