High Pressure Xenon Detectors for Rare Physics Searches
High Pressure Xenon Detectors for Rare Physics Searches
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用于稀有物理搜索的高压氙探测器
DOI：
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发表时间：
2014
期刊：
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通讯作者：
J. Renner
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文献类型：
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作者：
J. Renner
摘要：高压氙气探测器在寻找中微子双β (0νββ)衰变和暗物质与普通物质的相互作用等罕见物理过程方面具有重要的潜力。我们总结了这两种现象的物理和意义，并讨论了电致发光高压氙气时间投影室（TPC）的实验进展。该探测器是作为NEXT实验（氙TPC中微子实验）的原型而建造的，其目的是展示其探测电子反冲的能力，其能量分辨率足以进行强中微子双β衰变搜索。利用电致发光的低增益电离信号放大过程，我们能够在检测662 keV伽马射线时获得约1% FWHM的能量分辨率。此外，我们使用基于硅光电倍增管的跟踪平面展示了基本的粒子跟踪能力，这一技术也与NEXT方法搜索0νββ衰变相关。为了研究气态氙暗物质探测器的可能性，我们还对TPC中核反冲产生的电离和闪烁信号进行了表征，并将它们与电子反冲产生的相应信号进行了比较。核后坐力是用放射性同位素中子源产生的。我们的测量证明了在每个事件的基础上使用电离与闪烁的比率来区分电子和核反冲的能力，并提供了气态氙中核反冲的电离和闪烁产率的估计。最后，我们讨论了在惰性气体探测器中获得接近本征能量分辨率的另一种方法背后的物理原理。这种方法被称为负离子漂移，由有意将杂质引入捕获电离电子的气体介质中产生的漂移负离子组成。然后通过分离和放大它们携带的电子来对这些负离子进行计数。我们开发了一个基本的形式，试图理解离子漂移和分离过程，这是关键的实现这一技术。
Author(s): Renner, Joshua Edward | Advisor(s): Siegrist, James | Abstract: High pressure xenon gas detectors have the potential to significantly contribute to searches for rare physics processes such as neutrinoless double beta (0νββ) decay and interactions of dark matter with ordinary matter. We summarize the physics and implications of these two phenomena and discuss experimental developments conducted with an electroluminescent high pressure xenon time projection chamber (TPC).The detector was constructed as a prototype for the NEXT experiment - Neutrino Experiment with a Xenon TPC - and was intended to demonstrate an ability to detect electron recoils with an energy resolution sufficient for a strong neutrinoless double beta decay search. Using the low-gain ionization signal amplification process of electroluminescence, we are able to obtain an energy resolution of approximately 1% FWHM in the detection of 662 keV gamma rays. In addition, we demonstrate basic particle tracking capabilities using a silicon photomultiplier-based tracking plane, a technique also relevant to the NEXT approach in searching for 0νββ decay.To investigate the possibility of a gaseous xenon dark matter detector, we also characterize the ionization and scintillation signals produced by nuclear recoils in the TPC and compare them to the corresponding signals produced by electron recoils. The nuclear recoils are produced using radioisotope neutron sources. Our measurements demonstrate the ability to discriminate between electron and nuclear recoils using the ratio of ionization to scintillation produced on an event-by-event basis and provide an estimate of the ionization and scintillation yields of nuclear recoils in gaseous xenon.We end with a discussion of the physical principles behind another approach to obtaining nearly-intrinsic energy resolution in a noble gas detector. This approach, called negative ion drift, consists of drifting negative ions produced by intentionally introducing impurities into a gaseous medium that capture ionization electrons. These negative ions are then counted individually by detaching and amplifying the electron they carry. We develop a basic formalism in an attempt to understand the ion drift and detachment processes that are critical to the implementation of this technique.