Effect of Humidity on Scintillation Performance in Na and Tl Activated CsI Crystals
Effect of Humidity on Scintillation Performance in Na and Tl Activated CsI Crystals
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DOI：
10.1109/tns.2014.2300471
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发表时间：
2014-04-01
影响因子：
1.8
通讯作者：
Ohlhausen, James A.
中科院分区：
文献类型：
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作者：
Yang, Pin;Harmon, Charles D.;Ohlhausen, James A.
研究了钠（Na）和铊（Tl）激活的碘化铯（CsI）单晶在50%和75%相对湿度（RH）下的时间相关光致发光和辐射发光。这些结果表明，Tl活化的晶体比Na活化的晶体对湿度诱导的闪烁降解更稳健。“蚀坑”和“非活性”畴的发展是钠激活碘化铯晶体劣化的特征。这些“非活性”域，轴承下的晶体表面的多晶外观相似，可以很容易地检测到的250 nm的发光二极管。这些特征通常在角落和较深的划痕区域观察到，这些区域更可能发生水分冷凝。利用飞行时间二次离子质谱（ToF-SIMS）研究了钠激活碘化铯晶体闪烁降解的机理。ToF-SIMS深度分布表明，钠已优先扩散出碘化铯晶体，离开钠浓度在这些“非活性”域低于其闪烁阈值。
Time dependent photoluminescence and radioluminescence for sodium (Na) and thallium (Tl) activated cesium iodide (CsI) single crystals exposed to 50% and 75% relative humidity (RH) has been investigated. These results indicate that Tl activated crystals are more robust than the Na activated crystals against humidity induced scintillation degradation. The development of "etching pits" and "inactive" domains are the characteristics of deteriorated Na activated CsI crystals. These "inactive" domains, bearing a resemblance to a polycrystalline appearance beneath the crystal surface, can be readily detected by a 250 nm light emitting diode. These features are commonly observed at the corners and deep scratched areas where moisture condensation is more likely to occur. Mechanisms contributing to the scintillation degradation in Na activated CsI crystals were investigated by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). ToF-SIMS depth profiles indicate that Na has been preferentially diffused out of CsI crystal, leaving the Na concentration in these "inactive" domains below its scintillation threshold.