DEAP-3600 Installation, Commissioning and Analysis

众所周知，我们宇宙中的大部分物质都是黑暗的；目前，超过四分之三的物质无法直接观测。暗物质的起源和性质目前是粒子天体物理学中最重要的问题之一，全球对暗物质探测的积极研究证明了这一点。一个受欢迎的假设是暗物质由弱相互作用的大质量粒子组成，可以通过观察它们从原子核的弹性散射来探测。该提案将使在SNOLAB完成DEAP-3600实验并进行首次分析，用于非常敏感的暗物质搜索。DEAP-3600的独特之处在于利用闪烁脉冲的时间演变来区分背景事件的新技术，这导致了一个简单的探测器设计，可以缩放到非常大的目标质量。深埋地下的SNOLAB设施允许极低的背景，否则会掩盖暗物质信号。DEAP-3600将把对暗物质粒子的灵敏度提高100倍，从而可以对预测暗物质探测的理论模型进行测试。该项目已经开发了几年，目前正在安装在SNOLAB立方体大厅。中央探测器由一个大的（半径85厘米）丙烯酸容器组成，容器内装有3600公斤的低温液态氩，由255个光电倍增管观察，以探测核反冲产生的氩闪烁光脉冲。该实验将被安置在一个直径8米的水屏蔽箱中，并由甲板结构支撑，这两项工作都已在SNOLAB完成。探测器子系统（丙烯酸容器、氩气净化设备、读出电子设备和触发器以及相关基础设施）的安装预计将持续到2013年5月，之后探测器将被填充并准备进行数据收集。这项建议将导致在加拿大进一步培训高素质的人员。除了吸引学生和国际高水平的研究人员外，预计该申请支持的博士后研究员，RAs和学生将有机会参与这一前沿科学。

It is well-established that most of the matter in our universe is dark; more than three quarters of all matter currently evades direct observation. The origin and nature of this dark matter is currently one of the most important questions in particle astrophysics, evidenced by the active global research effort aimed at dark matter detection. 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 will enable the completion and first analysis of the DEAP-3600 experiment at SNOLAB for a very sensitive dark matter search. Unique to DEAP-3600 is the novel technique of discriminating background events using the time evolution of the scintillation pulse, which leads to a simple detector design that can be scaled to a very large target mass. Operation at the deep underground SNOLAB facility allows extremely low backgrounds which would otherwise mask dark matter signals. DEAP-3600 will increase sensitivity to dark matter particles by a factor of one hundred, allowing tests of theoretical models that predict dark matter detection is possible. The project has been under development for several years, and is currently being installed in the SNOLAB cube hall. The central detector consists of a large (85 cm radius) acrylic vessel which contains the 3600 kg cryogenic liquid argon and is viewed by 255 photomultiplier tubes to detect argon scintillation light pulses from nuclear recoils. The experiment will be housed in an 8 meter diameter water shielding tank and supported by a deck structure, both of which have been completed at SNOLAB. Installation of the detector subsystems (acrylic vessel, argon purification equipment, readout electronics and trigger, and associated infrastructure) is expected to continue until May 2013, after which the detector will be filled and prepared for data collection. This proposal will lead to further training of highly qualified personnel in Canada. In addition to attracting students and international highly qualified researchers, it is anticipated that the post-doctoral fellows, RAs, and students supported by this request will have the opportunity to take part in this leading-edge science.