DEAP-3600 Operation and Analysis

DEAP的合作非常活跃，在SNOLAB建造、实施和调试了DEAP-3600暗物质探测器。探测器的运行将在这项请求所涵盖的期间继续进行，并将需要大量的合作努力，并得到所需资金的支持。我们宇宙中暗物质的起源目前是粒子天体物理学中最重要的问题之一。众所周知，我们宇宙中的大部分物质都是暗的。一个有利的假设是，暗物质由WIMP组成，WIMP是相互作用很弱的大质量粒子，可以通过观察它们与原子核的弹性散射来检测到它们。这一提议是建立在使用液态氩进行灵敏暗物质搜索的研究基础上的。对于33GeV的WIMP质量，目前由LUX合作获得的与自旋无关的WIMP-核子截面的最佳极限约为7.6×10^-46 cm^2。将电流产生的实验扩大到更大的质量是至关重要的，因为目前的理论模型预测，在能够探测到暗物质粒子之前，可能需要将灵敏度提高几个数量级。我们的研究目标是对100GeV WIMP的10^-46 cm^2的WIMP-核子截面的灵敏度，以及对高质量WIMP的良好灵敏度。贵重液体作为低能粒子天体物理探测器引起了人们的极大兴趣，因为其中许多液体可以被清洁到极低的放射性水平，人们认识到这些液体可以用来建造非常大的目标质量探测器。DEAP-3600实验的独特之处在于根据闪烁脉冲的时间演变提供辨别能力的新技术。这导致了一种简单的探测器设计，可以缩放到非常大的目标质量。该探测器包括一个由光电倍增管(PMT)观察的大型球形丙烯酸容器，以允许记录Ar中闪烁事件的演变。每个事件的PMT位置将用于估计初始事件顶点，并用作外部源背景事件的主要拒绝，以允许大约1000公斤的基准目标质量的Ar。实验在一个直径约8米、高约8米的大型屏蔽池中进行。探测器的建造于2015年完成，合作伙伴一直在调试探测器系统并进行探测器校准，为液氮科学运行做准备。这项建议将导致HQP在加拿大的进一步培训。除了吸引学生和国际高素质的研究人员外，预计几名博士后研究员和研究助理将得到所需资金的支持，此外还将有技术人员在试验场开展工作。

The DEAP collaboration has been very active with construction, implementation and commissioning of the DEAP-3600 dark matter detector at SNOLAB. Operation of the detector will continue through the period covered by this request, and will require significant collaboration effort, enabled by the requested funds.The origin of the dark matter in our universe is currently one of the most important questions in particle astrophysics. It is well-established that most of the matter in our universe is dark. A favored hypothesis is that the dark matter consists of WIMPs, weakly interacting massive particles, which could be detected by observing their elastic scattering from nuclei. This proposal builds on research using liquid argon for a sensitive dark matter search. The current best limit on the spin-independent WIMP-nucleon cross-section is approximately 7.6x10^-46 cm^2 for a WIMP mass of 33 GeV, obtained by the LUX collaboration. Scaling the current-generation experiments to larger masses is critical since current theoretical models predict that improvements of sensitivity of several orders of magnitude may be needed before dark matter particles can be detected. Our research targets sensitivity to the WIMP-nucleon cross-section of 10^-46 cm^2 for a 100-GeV WIMP, and with good sensitivity to high-mass WIMPs. Noble liquids as low-energy particle astrophysics detectors have gained much interest since many of these can be cleaned to extremely low levels of radioactivity, and it is recognized that these can be used to build very large target mass detectors. Unique to the DEAP-3600 experiment is the novel technique of providing discrimination based on the time evolution of the scintillation pulse. This leads to a simple detector design that can be scaled to a very large target mass. The detector includes a large spherical acrylic vessel viewed by photomultiplier tubes (PMTs) to allow the recording of the evolution of a scintillation event in the argon. The PMT positions for each event will be used to estimate the initial event vertex, and serve as the primary rejection for external-source background events to allow a fiducial target mass of approximately 1000 kg of argon. The experiment resides in a large shielding tank approximately 8 meters in diameter and 8 meters high. Construction of the detector was completed in 2015, and the collaboration has been commissioning the detector systems and performing detector calibration, in preparation for the science run with liquid argon. This proposal will lead to further training of HQP in Canada. In addition to attracting students and international highly qualified researchers, it is anticipated that several post-doctoral fellows and RAs will be supported by the requested funds, in addition to technical personnel to enable operations at the experimental site.