Direct Dark Matter searches with LZ detector

大量的宇宙学和天体物理学证据不仅支持暗物质的存在，而且表明暗物质构成了我们宇宙的很大一部分质量。尽管如此，关于暗物质的很多东西仍然是未知的，包括暗物质的实际组成。LUX-ZEPLIN （LZ）是一个多探测器实验，旨在直接探测暗物质。特别希望观察到被认为是暗物质主要候选者之一的相互作用；弱相互作用大质量粒子。高灵敏度的LZ探测器（位于南达科他州）使用一个含有液态氙的时间投影室（TPC），目的是检测wimp -核相互作用。而LZ的外部探测器有助于抑制背景粒子的影响，背景粒子也可能在TPC中产生信号。这个博士项目的重点可以分为三个主要部分。第一种是基于硬件的；具体涉及利物浦LZ光学校准系统测试台的设置，以及FPGA固件的优化（特别关注光电二极管板的光强度测量）。除了有一个基于硬件的部分，这个项目还将有一个软件元素。本节的目的是帮助改进对LZ有用的数据分析和数据质量监测框架开发的优化和支持。最后，该项目的第三个方面将集中在物理数据分析上。这包括开发分析程序，以优化中子背景识别和抑制。以及物理分析框架的发展，利用简化的理论，目的是将LZ的结果与对撞机实验的暗物质搜索结果进行更直接的比较。

There is an abundance of both cosmological and astrophysical evidence, not only to support the existence of Dark Matter, but also to suggest Dark Matter makes up a great quantity of the mass of our universe. Despite this, much about Dark matter remains unknown, including what Dark matter actually consists of. LUX-ZEPLIN (LZ) is a multi-detector experiment that aims to directly detect Dark Matter. Specifically looking to observe interactions from what are considered to be one of the leading candidates for the building blocks of Dark Matter; WIMPS (Weakly Interacting Massive Particles). The highly sensitive LZ detector, (located in South Dakota), uses a Time Projection Chamber (TPC) containing liquid xenon with the aim of detecting WIMP-nucleus interactions. While the LZ's outer detector helps to suppress the effect of background particles which could also potentially produce signals in the TPC.The focus of this PhD project can be split into three main sections. The first of these being hardware based; specifically involving the setup of a test stand for the LZ Optical Calibration System in Liverpool, as well as optimization of FPGA firmware (particularly focusing on measurements of light intensities with photodiode boards). As well as having a hardware-based section, this project will also have a software element to it. The aim of this section being to help improve the optimisation and support in the development of the data analysis and data quality monitoring frameworks useful to LZ.Finally, the third aspect of this project will be focused on the physics data analysis. This includes the development of analysis procedures for optimization of neutron background identification and suppression. As well as the development of physics analysis framework, utilising simplified theories with the aim of this leading towards a more direct comparison of results from LZ to results with Dark Matter search results from collider experiments.