Measurement and tuning of beam parameters in the heavy ion storage ring ESR

The ESR is a cooler ring with a large momentum acceptance Delta p/p/sub 0/ of about 2.5%. It is possible to bound the Q variation in both transverse planes to less than 0.02, thereby allowing for RF stacking over the large momentum range without crossing resonances up to the fifth order. Tunes are measured very accurately in cooled beams via the BTF technique. The field quality in the large dipole magnets was improved by the excitation of pole face windings, leading to an improved linearization of natural chromaticity. Linear coupling due to large solenoid fields in the electron cooler can be detected and then corrected by auxiliary solenoids installed in the vicinity of the cooler. >