Population of high spin states in relativistic fragmentation

The population probabilities of isomeric states in the 10 ns to ms regime h ave been studied following their production via the fragmentation of a Pb-2 08 beam at 1 GeV per nucleon. Gamma decays from approximately 20 isomeric s tates, mostly in the A similar to 180 region, have been measured. Their cor responding isomeric ratios were compared with theoretical predictions based on the abrasion-ablation model of fragmentation, which appears to provide an upper limit for the measured population probabilities as a function of a ngular momentum.