Precision experiments with relativistic exotic nuclei at GSI

Abstract

Secondary beams of exotic nuclei have been produced in peripheral nuclear collisions with projectiles in the velocity range of 0.7-0.9 v/c provided by the heavy-ion synchrotron SIS at GSI. 8B, 11Be, and 19C nuclei have been studied in relativistic break-up reactions by using the projectile fragment separator FRS as a high-resolution energy-loss spectrometer. The experiments contribute to the knowledge of nuclear matter distribution for weakly-bound systems. A new era of experiments has been started with exotic nuclei separated by the FRS and stored and cooled in the experimental storage ring ESR. For instance, direct mass measurements of relativistic projectile fragments yield more than 100 previously unknown masses for isotopes in the range of54 ≤ Z ≤ 84. The data, characterized by an accuracy of about 100 keV, are compared to different mass models.