A crystal for a scintillator is a single crystal of Bi4Ge3O12 containing up to 0.5% by weight of Bi4Si3O12 and/or up to 50 ppm of Gd. The light output of this crystal as a scintillator can be increased by about 20% as compared with the light output of the conventional crystal of additive-free Bi4Ge3O12.
