The study of light yield increase after low dose rate irradiation in Y³⁺ doping PbWO₄ crystals

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• 作者：Zhang ; Xin ; Liao ; Jingying ; Li ; Peijun ; Yuan ; Hui ; Sheng ; Binfu ; Shao ; Peifa ; Li ; Changquan ; Yin ; Zhiwen
• 关键词：29.40.&minus ; n ; A1. Doping ; A2. Bridgman technique ; B1. Lead tungstate ; B2. Scintillator
• 刊名：Journal of Crystal Growth
• 出版年：2002
• 出版时间：April, 2002
• 年：2002
• 卷：240
• 期：1-2
• 页码：321-329
• 全文大小：316 K

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.