论文标题
开发液态氙气检测器的低背光光电倍增管
Development of low-background photomultiplier tubes for liquid xenon detectors
论文作者
论文摘要
我们成功地开发了一种新的光电倍增管（PMT），其直径为3英寸，凸形光电电极R13111。它的突出特征包括良好的性能和超低放射性。凸形光电模式实现了较大的光子接受和良好的计时分辨率。通过三个因素实现了低放射性：（1）使用低放射活性 - 污染材料合成玻璃材料； （2）使用$^{39} $ k-富集的钾产生光电极； （3）最纯净的铝材材料用于真空密封。结果，每个R13111 PMT仅包含$^{226} $ ra的0.4 MBQ，小于2 MBQ的$^{238} $ u，0.3 MBQ的$^{228} $ ra，2 MBQ，2 MBQ的$^{40} $ K和0.2 mbq of $ k和0.2 mbQ of $ k和0.2 mbq of $^of $^60} $ co。我们还检查并解析了XE气体在PMT中的固有泄漏，这些泄漏在几个较旧模型中观察到。因此，我们成功地开发了一个PMT，该PMT具有较低的背景，较大的角度接受，具有高收集效率，良好的时机解决方案和长期稳定操作。对于在标准模型之外搜索罕见事件的实验，例如暗物质粒子相互作用和中微子双β衰减事件，这些特征是非常需要的。
We successfully developed a new photomultiplier tube (PMT) with a three-inch diameter, convex-shaped photocathode, R13111. Its prominent features include good performance and ultra-low radioactivity. The convex-shaped photocathode realized a large photon acceptance and good timing resolution. Low radioactivity was achieved by three factors: (1) the glass material was synthesized using low-radioactive-contamination material; (2) the photocathode was produced with $^{39}$K-enriched potassium; and (3) the purest grade of aluminum material was used for the vacuum seal. As a result each R13111 PMT contains only about 0.4 mBq of $^{226}$Ra, less than 2 mBq of $^{238}$U, 0.3 mBq of $^{228}$Ra, 2 mBq of $^{40}$K and 0.2 mBq of $^{60}$Co. We also examined and resolved the intrinsic leakage of Xe gas into PMTs that was observed in several older models. We thus succeeded in developing a PMT that has low background, large angular acceptance with high collection efficiency, good timing resolution, and long-term stable operation. These features are highly desirable for experiments searching for rare events beyond the standard model, such as dark matter particle interactions and neutrinoless double beta decay events.
