Fig. 2

Production efficiency of 169Er by irradiation of natural erbium in low (neutron flux 1βΓβ1013 neutrons/cm2/sec), medium (neutron flux 1βΓβ1014 neutrons/cm2/sec) and high (neutron flux 1βΓβ1015 neutrons/cm2/sec) flux reactors. Cooling time 0 days.