The population probabilities of isomeric states in the 10 ns to ms regime have been studied following their production via the fragmentation of a ²⁰⁸Pb beam at 1 GeV per nucleon. Gamma decays from approximately 20 isomeric states, mostly in the A \sim 180 region, have been measured. Their corresponding 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 angular momentum.

PACS numbers: 25.70.Mn, 27.80.+w