XENON FUTURES: R&D FOR A GLOBAL RARE EVENT OBSERVATORY (PHASE 2)

这项建议描述了一项为期3年的研究和开发计划，以应对下一代液体氙基暗物质探测器将面临的一些最重要的挑战，并将使英国能够保持和提高其全球声誉。天体物理和宇宙学证据已经建立了宇宙学的标准模型，它表明暗物质对宇宙总密度的贡献~27%。在英国博尔比运行的ZEPLIN实验计划开创了用于暗物质搜索的LXE技术。这种设计本质上是可扩展的，其大小足以最大限度地受益于自我屏蔽，自那以来，LXE探测器一直是寻找暗物质散射的世界领先技术。这一提议的支持者成功地为目前最先进的第二代LUX-ZEPLIN(LZ)实验做出了重大贡献。随着LZ于2020年底进入数据采集和开发阶段，现在正是开始研究和开发未来液体氙气探测器的时候。这个为期3年的研发项目是为了开发和准备英国为未来的第三代液体氙气(G3)全球稀有事件天文台做出的贡献。这将把搜索灵敏度扩大到新的中微子背景将在哪些地方成为暗物质候选者的主导，也将延伸到较低的质量，对于这些候选者来说，他们受到的约束较少，但动机也同样良好。这一研发阶段的主要目标是通过米格达尔效应展示灵敏度，并开发可扩展的低本底VUV-SiPM光电传感器阵列及其读出系统，从而提高G3实验的科学覆盖面。

This proposal describes a 3-year programme of research and development into some of the most important challenges to be faced by next-generation liquid xenon-based dark matter detectors, and will enable the UK to maintain and enhance its global reputation. Astrophysical and cosmological evidence has established the Standard Model of Cosmology, which indicates that dark matter contributes ~27% to the total density of the universe. The ZEPLIN programme of experiments, operated at Boulby (UK), pioneered the LXe technology for dark matter searches. The design is inherently scalable and, with sizes large enough to benefit maximally from self-shielding, LXe detectors have been the world-leading technology in searches for dark matter scattering ever since. The proponents of this proposal successfully delivered major contributions to the current state-of-the-art 'Generation 2' LUX-ZEPLIN (LZ) experiment. With LZ entering its data-taking and exploitation phase in late 2020, it is timely to start research and development for future liquid xenon detectors now. This 3-year R&D project is for developing and preparing UK contributions for a future liquid xenon Generation 3 (G3) Global Rare Event Observatory. This will extend the search sensitivity right down to where new neutrino backgrounds will become dominant for masses of dark matter candidates >5 GeV, and also to lower masses, for which candidates are less well-constrained but equally well-motivated. The main aims of this R&D phase are to enhance the scientific reach of a G3 experiment through demonstrating sensitivity via the Migdal effect and developing scalable low background VUV-SiPM photosensor arrays and their readout systems.