A search for the last neutrino flavour mixing angle with the T2K experiment and development of novel detector technique for safeguards application

在过去的十年里，一系列实验证明了中微子领域最惊人的发现之一：中微子有质量，它们会振荡。这是标准模型无法描述的现象的第一个令人信服的证据，它已经对天体物理学和宇宙学产生了重大影响。它也可能使我们进一步发现轻子扇区中的CP违背，就像在夸克扇区中存在CP违背一样。这将是至关重要的，因为CP违背被认为是宇宙中物质和反物质不对称的起源机制，但仅在夸克扇区中太小，无法解释所有的不对称。只有在发生介子中微子到电子中微子的振荡时，才有可能在中微子扇区中获得CP违逆。本研究有两个主要目标：1。利用日本T2K实验寻找介子中微子到电子中微子的振荡；和2。领导开发一种基于T2K探测器技术的反中微子监测器，用于保障应用。T2K是一个长基线中微子实验，其主要目标是在振荡的μ子中微子束中寻找电子中微子的出现。介子中微子束是在东海（日本东北部）的J-PARC设施中产生的，并在295公里外的神冈矿的大型水切伦科夫超级神冈探测器中被探测到。这项研究的重点是在光束有时间振荡之前在T2K附近探测器上测量中微子相互作用。这些测量将用于描述超级神冈的背景相互作用，以便最大限度地提高我们发现这种振荡的机会。T2K近距离探测器所使用的技术已被发现非常适合应用于核反应堆监测。反应堆堆芯是强大的中微子源，能提供有关反应堆运行的精确信息。使用高性能、实用和具有成本效益的中微子探测器已被确定为非常适合未来实施国际原子能机构（IAEA）保障程序。这项研究将引领能够完成这项任务的设备的发展，这将是中微子物理学的第一个实际应用。

In the last ten years a combination of experiments has demonstrated one of the most striking discoveries in the neutrino sector: neutrinos have mass and they oscillate. This is the first compelling evidence for a phenomena that is not described by the standard model and which has already had great consequences for astrophysics and cosmology. It might also bring us further to the discovery of CP violation in the lepton sector in a similar way that CP violation is present in the quark sector. This will be of utmost importance as CP violation is a mechanism believed to be at the origin of matter and anti-matter asymmetry in the universe but too small in the quark sector alone to explain all of it. Accessing CP violation in the neutrino sector is only possible if oscillation of muon neutrino to electron neutrino takes place. This research has two key objectives: 1. to search for the oscillations of muon neutrino to electron neutrino using the T2K experiment in Japan; and 2. to lead the development of an anti-neutrino monitor for safeguards applications based on T2K detector techniques. T2K is a long baseline neutrino experiment, whose main goal is to look for appearance of electron neutrinos in an oscillated beam of muon neutrinos. The muon neutrino beam is created at the J-PARC facility in Tokai (north-east Japan) and detected 295 km away in the large water Cherenkov detector Super-Kamiokande in the Kamioka mine. This research focuses on measurement of neutrino interactions at the T2K near detector before the beam has had time to oscillate. These measurement will be used to characterise background interactions at Super-Kamiokande in order to maximise our chance of discovering this oscillation. Technology based used at the T2K near detector has been found to be well suited for application in nuclear reactor monitoring. Reactor cores are powerful neutrino sources and give precise information about the reactor operation. The use of high performance, practical and cost-effective neutrino detector has been identified as being well suited for future implementation of the International Atomic Energy Agency (IAEA) safeguard procedures. This research would lead the way in the development of a device capable of performing this task which would be the first practical application of neutrino physics.