Production cross-sections of neutron-rich Pb and Bi isotopes in the fragmentation of 238 U

Neutron-rich lead and bismuth isotopes have been produced by cold-fragmentation reactions induced by 238 U projectiles at 1A GeV impinging on a beryllium target. The high-resolving power FRagment Separator (FRS) at GSI allowed us to identify and determine the production cross-sections of 43 nuclei, nine of them for the first time ( 216, 217, 218, 219 Pb and 219, 220, 221, 222, 223 Bi . These data are compared to other previously measured cross-sections in similar reactions and model calculations.