Effective enhancement of light yield achieved in Bi4Si3O12 scintillation single crystals by doping with tantalum ions

Bismuth silicate (Bi4Si3O12, BSO) crystal is considered as a promising candidate for fabricating dual-readout calorimeters. Ta2O5 doped BSO crystals were successfully grown by the modified vertical Bridgman method. The crystals possessed about 80% transmittance in the region of 350–800 nm with an absorption edge at about 280 nm. The emission and excitation spectra only showed a wide band which could be ascribed to the typical peaks of Bi3+. The light yield of BSO crystals could be improved effectively by doping Ta2O5, and the optimized concentration was about 1 mol%, dramatically improving the light output to about 150% of pure BSO crystals. Both the experimental results and theoretical calculations showed that doping Ta5+ ion could reduce the band gap and effectively enhance the light absorption, which was beneficial to generate more electron-hole pairs and promote its emission and light yield. Ta5+ ion is an effective candidate among the transition metal ions for improving the light output of BSO crystals.