La-doped PbWO4 scintillating crystals grown in large ingots

We achieved a significant increase in the ingot size of La-doped PbWO4 single crystals to 65 mm in diameter and 300 mm in length by using the Czochralski technique and three times of recrystallization. Four blocks each with a typical size of 20×20×230 mm3 were taken from an ingot. The optical as well as the scintillation characteristics of the large-size crystals, including the radiation hardness, were found to be similar to or even better than those of smaller crystals. The radiation-induced absorption coefficient μir was as small as 0.5–1 m−1 at 107 rad of 60Co γ-ray irradiation.