Y3+:PbWO4晶体低剂量辐照行为研究

三价稀土离子（La^3 ,Lu^3 ,和Y^3 等）掺杂显著地提高了钨酸铅晶体的辐照硬度，但是部分Y^3 掺杂钨酸铅晶体表现出特殊的低剂量辐照行为，即光产额辐照后升高，并且辐照硬度对退火温度较敏感，研究研究挑选了存在这一现象的Y^3 :PbWO4晶体，测试冰同温度的退火处理对晶体透过率，光产额和辐照硬度的关系，发现，辐照后光产额升高的现象同时存在于晶体的晶种端，而不是只集中在晶体顶端，并且和辐照前后晶体在400－500nm波段附近的透过率变化有关；生长态Y^3 :PbWO4晶体中导致430nm吸收带的色心的稳定性很低，低剂量辐照对该色心有“漂白”作用，辐照剂量率加大则晶体表现出光产额的降低，分段晶体的系列退火实验解释了辐照硬度对退火温度较为敏感这一现象，为进一步深入研究提供了实验基础。

Low Dose Rate Radiation Behaviors of Y3+ Doping PbWO4 Crystals

Although trivalent ions (such as La3+, Lu3+ and Y3+) doping can significantly improve the radiation hardness of lead tungstate crystals, some Y3+ doping PWO crystals show exceptional behaviors under low dose rate radiation, namely, the light yield increases even exposed to UV irradiation. In addition the radiation hardness is sensitive to annealing temperature. In this study some Y3+ doping crystal samples that have the phenomenon mentioned above were chosen and the relationship between transmission and light yield of the samples investigated. The experimental results show that the increase of light output not only exists in the topside of the crystals, but also in the seed side, and is accompanied with optical transmission change from 380nm to 500nm simultaneously. The as grown and annealing induced 430nm color centers are unstable and can be " bleached " by low dose rate irradiation. The results of series annealing experiments of the sample segments can interpret the phenomenon that radiation hardness is sensitive to annealing temperature.