Production of neutron-rich heavy residues and the freeze-out temperature in the fragmentation of relativistic 238U projectiles determined by the isospin thermometer Original Research Article

Isotope yields of heavy residues produced in collisions of 238U with lead at 1A GeV show indications for a simultaneous break-up process. From the average N-over-Z ratio of the final residues up to Z=70, the average limiting temperature of the break-up configuration at freeze out was determined to T≈5 MeV using the isospin-thermometer method. Consequences for the understanding of other phenomena in highly excited nuclear systems are discussed.