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

天体物理学和宇宙学的证据已经建立了宇宙学的标准模型，该模型表明，只有不到5%的宇宙是由我们认为可以理解的物质组成的，剩下的95%是由暗物质和暗能量组成的。据推测，暗物质占宇宙总密度的27%。现有的暗物质探测器，包括2019年正在建设的LUX-ZEPLIN (LZ)，主要用于探测wimp（弱相互作用大质量粒子）与普通原子核的碰撞——在LZ的特定情况下，在液态氙目标中。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态氙探测器是及时的。这个为期3.5年的研发项目是为了开发和准备英国对未来第三代液态氙（G3）全球罕见事件天文台的贡献。在英国博尔比（Boulby）运行的ZEPLIN实验项目开创了暗物质搜索的LXe技术。这种设计具有固有的可扩展性，并且由于尺寸足够大，可以最大限度地从自屏蔽中受益，从那时起，LXe探测器一直是世界领先的暗物质散射搜索技术。支持者们已经成功地完成了英国对第二代（G2）实验LZ的贡献，最终的G3实验将建立在此基础上，并将搜索灵敏度扩展到新的中微子背景，在那里，新的中微子背景将成为bbbb5 GeV的暗物质候选者的主导，以及更低质量的候选者，它们受到的约束较少，但同样有很好的动机。这一研发阶段的主要目的是通过米格达尔效应来展示灵敏度，探索氙与轻元素的掺杂，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实验的概念设计做出重大贡献，从而提高G3实验的科学范围。

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 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 - 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 3.5-year R&D project is 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 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 have delivered successfully the UK contribution to the Generation 2 (G2) experiment LZ, 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 - and also to 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 design of the G3 experiment.