Abstract The distorted-perovskite scintillator materials CsCaI 3 :Eu and CsSrBr 3 :Eu prepared as single crystals have shown promising potential for use in radiation detection applications requiring a high light yield and excellent energy resolution. We present a study using high temperature powder X-ray diffraction experiments to examine a deleterious high temperature phase transition. High temperature phases were identified through sequential diffraction pattern Rietveld refinement in GSAS II. We report the linear coefficients of thermal expansion for both high and low temperature phases of each compound. Thermal expansion for both compositions is greatest in the [0 0 1] direction. As a result, Bridgman growth utilizing a seed oriented with the [0 0 1] along the growth direction should be used to mitigate thermal stress.

中文翻译：

---

CsCaI 3 :Eu 和 CsSrBr 3 :Eu 闪烁体的晶体结构和热膨胀

摘要 制备为单晶的畸变钙钛矿闪烁体材料 CsCaI 3 :Eu 和 CsSrBr 3 :Eu 已显示出在需要高光输出和出色能量分辨率的辐射检测应用中的应用潜力。我们提出了一项研究，使用高温粉末 X 射线衍射实验来检查有害的高温相变。通过 GSAS II 中的连续衍射图 Rietveld 精修确定高温相。我们报告了每种化合物的高温和低温相的线性热膨胀系数。两种组合物的热膨胀在[0 0 1]方向上最大。因此，应该使用沿生长方向以 [0 0 1] 取向的种子的布里奇曼生长来减轻热应力。