文摘
Although trivalent ions (such as La3+, Lu3+ and Y3+) doping can significantly improve the radiation hardness of lead tungstate crystals, some Y3+ doping PbWO4 (PWO) crystals showed exceptional irradiation behavior, namely, light yield increase after low dose rate irradiation. In addition the radiation hardness was sensitive to annealing temperature. In this study, we chose typical Y3+ doping crystal samples and investigated the relationship between transmission, light yield and radiation hardness. The experimental results show that high temperature annealing can enhance the absorption band around 430nm, while annealing at 50°C produces different results and can suppress this exceptional behavior. Light output increase not only exists in the top side of the boule, but also in the seed side, and is accompanied with optical transmission change in the wavelengths from 380nm to about 500nm simultaneously. The pre-existing 430nm color centers in as-grown PWO:Y3+ or annealing induced ones are unstable and can be “bleached” by low dose rate irradiation. The results of annealing and irradiation experiments of the samples show that the radiation hardness phenomenon was sensitive to annealing temperature, and thus a proper annealing temperature for PWO crystals was determined.