Fig. 11

Change in the radioisotopic purity of 169Er with cooling time. Open Circle β Natural erbium irradiated in low-flux reactor (reactor flux 1βΓβ1013 neutrons/cm2/sec) for 21 days. Closed Circle β Enriched erbium irradiated in low-flux reactor (reactor flux 1βΓβ1013 neutrons/cm2/sec) for 21 days.