Infrastructure Request for High Pressure Gas TPC Development Studies for the DUNE Near Detector

宇宙中的反物质是如此微不足道，以至于我们的世界存在的时间足够长，足以让智慧生命进化。但我们的知识却并非如此：根据这本书，所有的物质都应该与等份的反物质一起湮灭。解开这个谜团的唯一钥匙来自中微子和反(物质)中微子之间的行为差异，这可以通过基于加速器的中微子实验来研究。有了更强大的加速器和尖端的探测器，我们正在以前所未有的精度研究中微子相互作用。深层地下中微子实验(DUNE)是美国的下一代中微子实验，旨在寻找中微子和反中微子之间的微小不对称，并寻找源自粒子物理标准模型以外的物理学的罕见事件。沙丘将通过测量中微子振荡来做到这一点，中微子从费米实验室产生的中微子到1200公里外的远探测器(FD)探测到的过程中，中微子会改变类型。沙丘-英国项目是美国以外最大的沙丘贡献，将对该实验的建设做出重大贡献。它目前的重点是沙丘数据采集(DAQ)、FD和光束线的建设。FD模块计划从2027年开始上线，随后波束将于2030年上线，近距离探测器(ND)将于2032年上线。Nd复合体由液态Ar TPC、由螺线管和量热计封闭的高压气体时间投影室(HPgTPC)和轴上束流监视器组成。这个复合体的设计是为了精确地描述中微子束，并以前所未有的细节研究中微子与原子核的相互作用，以便更好地理解导致振荡测量的各个系统误差。目前正在设计中的沙丘ND的HPgTPC将成为研究中微子相互作用的最终探测器，因为它的探测阈值非常低，角度接受度很高，而且非常大的高压气体体积提供了巨大的目标质量。最近，概念设计报告已经出版，技术设计报告(TDR)目前正在编制中。虽然美国的合作者在HPgTPC的磁体和机械设计方面处于领先地位，但英国的机构参与了气体研究、读出技术开发、电子和数据采集设计以及读出室的束流测试。我们建议在华威大学建立一个HPgTPC研发平台。它由三项原型设备组成：1.高性能TPC，2.高性能光学读出系统，3.激光-放射性气体校准系统。虽然我们正在通过前两件设备巩固我们在气体研究和读出技术开发领域的领先地位，但拟议的激光校准系统旨在为被认为是TDR高度优先的HPgTPC气体质量控制提供技术解决方案。该方案中的平台将为英国的加速器-中微子气体TPC研发提供唯一的本地支持。这项提议的资本资助将非常及时地推动在英国进一步研发HPgTPC概念，并将很好地补充扩大英国对沙丘附近探测器项目的贡献的努力。

Antimatter in the universe is so negligible that our world exists long enough for intelligent life to evolve. But our knowledge says otherwise: By the book, all matter should have obliterated together with antimatter in equal parts. The only key to unlocking this puzzle comes from the behavioural difference between neutrinos and anti(matter-)neutrinos, which can be studied by accelerator-based neutrino experiments. With more powerful accelerators and sophisticated detectors, we are on the way to examining neutrino interactions with unprecedented precision. The Deep Underground Neutrino Experiment (DUNE) is the next-generation neutrino experiment in the US designed to look for the tiny asymmetry between neutrinos and antineutrinos and search rare events that originate from physics beyond the Standard Model of particle physics. DUNE will do this by measuring neutrino oscillations, a phenomenon where neutrinos change type on their way from their production at Fermilab to their detection by the Far Detector (FD) 1200 km away. The DUNE-UK project is the biggest DUNE contribution outside the US and will contribute significantly to the construction of the experiment. It currently focuses on the construction of the DUNE data acquisition (DAQ), FD, and the beamline. The FD modules are planned to be online from 2027, followed by the beams in 2030, and the near detector (ND) in 2032. The ND complex consists of a liquid argon TPC, a High Pressure gas Time Projection Chamber (HPgTPC) enclosed by a solenoid and a calorimeter, and an on-axis beam monitor. This complex is being designed to precisely characterise the neutrino beams and to study neutrino-nucleus interactions with unprecedented details so that the respective systematic errors contributing to the oscillation measurements are much better understood. The HPgTPC of the DUNE ND, currently being designed, will be the ultimate detector to study neutrino interactions due to its very low detection threshold, full angular acceptance, and very large high-pressure gas volume providing a large target mass. Recently, the Conceptual Design Report has been published, and the Technical Design Report (TDR) is currently being prepared. While the US collaborators are leading the R&D in the magnet and mechanical designs of the HPgTPC, UK institutions are involved in gas studies, readout technology development, design of electronics and DAQ, and in a beam test of the readout chambers. We propose to build an HPgTPC R&D Platform at the University of Warwick. It consists of three items of prototype equipment:1. a HPgTPC,2. a high-performance optical readout system, and3. a laser-radioactive gas-calibration system.While we are consolidating our leadership in the field of gas studies and readout technology development with the first two pieces of equipment, the proposed laser calibration system aims to provide a technical solution to the HPgTPC gas quality control that is considered a high priority for the TDR. The Platform in this proposal will provide the only local support for accelerator-neutrino gas TPC R&D in the UK. Capital funding for this proposal would represent a very timely push for further R&D into the HPgTPC concept in the UK and would complement well efforts to extend UK contributions to the DUNE Near Detector project.