We examined the effect of the radiation damage on optical and scintillation properties of BGO crystals produced by the low-thermal-gradient Czochralski growth technique. Irradiation tests were performed for gamma -ray doses from 1 krad to 10 Mrad. Optical absorption and light output were measured upon irradiation and self-recovery. Based on the shape of radiation-induced absorption, degradation of transparency and light output upon radiation damage as well as their self-recovery. two distinct types of BGO crystals were established. (C) 2001 Elsevier Science B.V. All rights reserved.