YAlO3∶Ce晶体的生长及性能研究

本文采用中频感应提拉法生长了尺寸为ø35 mm×70 mm的完整的YAlO₃∶Ce(YAP∶Ce)晶体。XRD测试结果表明所生长的YAP∶Ce晶体主相为YAP相,同时存在第二相YAG相;光致激发发射光谱表明晶体发射波长在344 nm和376 nm,激发波长分别为273 nm、290 nm和305 nm;X射线激发发射光谱表明晶体发射波长在377 nm附近;在γ高能射线激发下,晶体衰减时间曲线呈指数衰减,拟合后得到YAP∶Ce晶体的衰减时间为46 ns,通过高斯拟合以后YAP∶Ce晶体的能量分辨率和绝对光产额分别为8.51%和8 530 ph/MeV。本文分析了晶体生长过程中产生开裂和相变的原因,通过优化温场和工艺可以得到完整无开裂的晶体。如何获得更大尺寸的无开裂、无相变晶体,并实现量产是该晶体规模化应用中需要解决的重要技术难题。

Growth and Properties of YAlO3∶Ce Crystal

In this paper, crack-free YAlO₃∶Ce (YAP∶Ce) crystals with size of ø35 mm×70 mm were grown by medium frequency induction Czochralski method. XRD results show that the main phase of YAP∶Ce crystal is YAP phase and the second phase is YAG phase. Photoluminescence emission spectra show that the emission wavelengths of the crystal are located at 344 nm and 376 nm, and the excitation wavelengths are located at 273 nm, 290 nm and 305 nm respectively. X-ray emission spectrum shows that the crystal emission wavelength is around 377 nm. The decay time curve of YAP∶Ce crystal decreases exponentially under the excitation of γ high-energy rays. After exponential decay fitting, the decay time of YAP∶Ce crystal is 46 ns. After Gaussian fitting, the energy resolution and absolute light yield of YAP∶Ce crystal are 8.51% and 8 530 ph/MeV respectively. The reasons of cracking and phase transition during crystal growth were analyzed. The crack-free crystals can be obtained by optimizing temperature fields and processes. How to obtain larger size crystals without cracking, phase transition and achieve their mass production is an important technical problem to be solved in the large-scale application of the crystal.