Recent Results from ESR

Abstract

The ESR storage ring has been designed for high resolution and high precision experiments with highly charged ions, both stable and radioactive species. Stochastic and electron cooling provide fast and powerful cooling for the preparation of cold ion beams. For small ion beam intensities beams of unprecedented quality can be obtained by electron cooling. The internal gas jet target allows operation with a variety of gases. The highly charged ions can be decelerated to reduce the resolution limitation originating from Doppler effects. The decelerated ions are either used for internal experiments or extracted to a fixed target area with an ultraslow extraction mode. For the determination of the masses of radioactive nuclei two methods have been developed. Schottky mass spectrometry of cooled ions with nuclear lifetimes of the order of seconds or longer allows mass measurements by determination of the revolution frequency from the Schottky noise with a mass resolution of 1 ppm. Tuning of the focusing structure of the storage ring to the transition energy of 344 MeV/u is applied to measure the masses of short–lived nuclei by a time of flight method.