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研究了掺铈铝酸钇(Ce:YAP)晶体的自吸收机理以提高其光产额等闪烁性能。用提拉法生长了不同掺杂摩尔分数的Ce:YAP闪烁晶体。室温下测试了不同厚度、不同摩尔分数和不同退火条件下Ce:YAP晶体的透过、荧光、X射线激发发射等光谱特征,并对可能存在的自吸收机理进行了分析。结果表明,Ce:YAP晶体的自吸收主要由Ce4+离子与氧离子配体之间的电荷转移吸收引起,根据电荷转移吸收理论可得其吸收峰在303 nm左右,与实验结果基本一致。本实验表明通过一定的退火工艺和掺杂控制减少Ce4+离子,将能有效地使样品的吸收边蓝移,从而减少Ce:YAP晶体的自吸收,提高闪烁性能。
The self-absorption mechanism of cerium-doped yttrium aluminate (Ce: YAP) crystal was studied to improve the scintillation properties such as its light yield. Ce: YAP scintillation crystals with different doping mole fractions were grown by Czochralski method. The spectral characteristics of Ce: YAP crystal under different thickness, molar fraction and annealing conditions were tested at room temperature, and the possible self-absorption mechanism was analyzed. The results show that the self-absorption of Ce: YAP crystals is mainly caused by the charge transfer between Ce4 + ions and oxygen ion ligands. According to the theory of charge transfer absorption, the absorption peak is about 303 nm, which is consistent with the experimental results. This experiment shows that the Ce4 + ions can be effectively blue-shifted by reducing the amount of Ce4 + ions through a certain annealing process and doping control, thus reducing the self-absorption of Ce: YAP crystals and improving the scintillation performance.