The Darkside-20k Dark Matter Detector

银河系暗物质的探测及其基本性质的建立是粒子物理学中的一个非常重要的问题。最灵敏的直接搜索高质量WIMP(弱相互作用大质量粒子)暗物质使用大型液体稀有气体探测器来搜索核反冲。我们的目标是一个在液态Ar中的程序，以降低对大气中微子相干散射在探测器中并产生模拟WIMP暗物质的反冲所引起的“中微子底”的灵敏度。这一目标导致了世界上所有的Ar暗物质研究人员联合在一起，组成了一个全球Ar暗物质合作。我们目前的探测器，名为DEAP-3600，包含约3.3吨液体Ar，位于法国SNOLAB，是目前世界上最灵敏的Ar暗物质探测器。DEAP已经证明了液体Ar的光发射特性，使其能够对中微子层的氡和太阳中微子等其他背景进行大于108的分辨。这项提议正在请求支持，以使加拿大研究人员能够参与“Darkside-20k”探测器，这是一个大型液体Ar时间投影室(TPC)，将位于意大利的Gran Sasso实验室，将把液体Ar暗物质探测的范围扩大一个数量级。加拿大集团已经开始致力于Darkside--20k计划的几个方面，特别是在他们过去有丰富经验的领域：硅光电倍增管数据采集系统和电子、地下氩工厂以及随后的存储和工艺、探测器的设计、将在加拿大用丙烯酸制成的独特的TPC、用TPC元件和TPB制造和涂层丙烯酸的程序以及用于波长漂移的TPB。与这些活动相关的主要资本成本已在CFI的另一份提案中提出，总价值为2200万美元。Darkside-20K将拥有可以现场测量的超低背景。这将对1TeV/c2(10TeV/c2)质量的WIMP--1.2x10-47cm2(1.1x10-46cm2)的WIMP-核子截面提供灵敏度，将在没有任何仪器背景的情况下在5年内实现100吨的照射。在意大利的实验完成后，他们的计划是建造一个更大的400吨(Argo)探测器，该探测器将位于萨德伯里的SNOLAB地下实验室。。

The detection of galactic dark matter and the establishment of its fundamental properties are a very high priority in particle physics. The most sensitive direct searches for high mass WIMP (weakly interacting massive particle) dark matter use large liquid noble gas detectors to search for nuclear recoils.Our objective is a program in liquid argon to reach down in sensitivity to the "Neutrino Floor" caused by atmospheric neutrinos coherently scattering in the detector and generating recoils that simulate WIMP dark matter. This objective has resulted in the joining together of all the argon dark matter researchers in the world, to form a global argon dark matter collaboration.Our current detector, called "DEAP--3600", contains about 3.3 tonnes of liquid argon, is situated in SNOLAB,  and is currently the most sensitive argon dark matter detector in the world. The light emission properties of liquid argon have already been demonstrated in DEAP to enable discrimination greater than 108 against other backgrounds such as radon and solar neutrinos at the Neutrino Floor.  This proposal is requesting support to enable Canadian researchers to participate in the "Darkside--20k" detector, a large liquid argon time projection chamber(TPC) that will be situated in the Gran Sasso Laboratory in Italy that will extend the reach of liquid argon dark matter detection by an order of magnitude. Canadian groups have started to work on several aspects of the DarkSide--20k program, particularly in areas where they have strong past experience: the silicon-photomultiplier data acquisition system and electronics, the underground argon plant and subsequent storage and processes, the design of the detector, the unique TPC to be built from acrylic in Canada, and the procedures to fabricate and coat acrylic with resistive coatings for TPC components and with TPB for wavelength shifting. The main capital costs associated with these activities have been requested in a separate CFI proposal, with a total value of $22M. DarkSide-20k will have ultra-low backgrounds that can be measured in situ. This will give sensitivity to WIMP--nucleon cross sections of 1.2 x 10--47 cm2(1.1 x 10-46 cm2) for WIMPs of 1 TeV/c2 (10 TeV/c2) mass, to be achieved during a 5 year run producing an exposure of 100 tonne--year free from any instrumental background. After the experiment in Italy is complete, the plan is to build an even larger detector of 400 tonnes (Argo) that will be located at the SNOLAB underground laboratory in Sudbury.  .