XENON FUTURES: R&D for a Global Rare Event Observatory - Phase 1

天体物理学和宇宙学证据已经建立了宇宙学的标准模型，该模型表明，宇宙中只有不到5%的物质是由我们认为自己理解的物质组成的，其余的95%由暗物质和暗能量共享。暗物质对宇宙总能量密度的贡献约为27%。现有的暗物质探测器，包括2019年在建的LUX-ZEPLIN(LZ)，主要用于探测WIMP(弱相互作用大质量粒子)与普通核的碰撞-在LZ的特定情况下，WIMP包含在液体氙靶中。随着LZ在2020年进入数据采集和开发阶段，现在开始研究和开发未来的液体氙气探测器是适时的。这个为期18个月的项目是一个更广泛的研发计划的第一阶段，该计划旨在为未来的第三代液体氙气(G3)全球稀有事件天文台开发和准备英国的贡献。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液体氙气技术。这种设计本质上是可扩展的，尺寸足够大，可以最大限度地从自我屏蔽中受益，自那以来，这些探测器一直是寻找暗物质散射的世界领先技术。支持者已经成功地为即将启动的第二代(G2)实验LZ提供了英国的贡献，最终的G3实验将建立在这一基础上，并将搜索灵敏度扩展到新的中微子背景将成为主导&gt；5Gev的大量暗物质候选的地方。通过这项研发，G3实验还将针对较低质量，即较少受到良好约束但同样具有良好积极性的候选人。这一研发阶段的主要目标是通过展示Migdal效应的敏感性，探索轻元素掺杂氙气，开发可扩展的VUV-SiPM读出系统作为PMT的潜在替代品，减少背景(特别是氡)，并为G3实验的概念和初步设计做出重大贡献，从而增强G3实验的科学影响。

Astrophysical and cosmological evidence has established the Standard Model of Cosmology which suggests that less than 5% of the universe is made of matter that we believe we understand, with the remaining >95% shared between dark matter and dark energy. Dark matter is suggested to contribute ~27% to the total energy density of the universe. Existing dark matter detectors, including those under construction in 2019 such as LUX-ZEPLIN (LZ), are primarily geared towards detecting the collisions of WIMPs (Weakly Interacting Massive Particles) with ordinary nuclei - contained in a liquid xenon target in the specific case of LZ. With LZ entering its data-taking and exploitation phase during 2020, it is timely to start research and development for future liquid xenon detectors now. This 18-month project delivers the first phase of a wider R&D programme for developing and preparing UK contributions for a future liquid xenon Generation 3 (G3) Global Rare Event Observatory. The ZEPLIN programme of experiments, operated at Boulby (UK), pioneered the liquid xenon technology for dark matter searches. The design is inherently scalable and, with sizes large enough to benefit maximally from self-shielding, these detectors have been the world-leading technology in searches for dark matter scattering ever since. The proponents have delivered successfully the UK contribution to the Generation 2 (G2) experiment LZ which is about to switch on, and an ultimate G3 experiment will build on that and extend the search sensitivity right down to where new neutrino backgrounds will become dominant for masses of dark matter candidates of >5 GeV. Through this R&D, a G3 experiment will also address lower masses, which are less well-constrained but equally well-motivated candidates.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, exploring xenon doping with light elements, developing scalable VUV-SiPM readout systems as potential replacements for PMTs, reducing backgrounds (especially radon), and producing significant contributions to the conceptual and preliminary designs of the G3 experiment.