Collaborative Research: Next Generation CMB Polarization Measurements withthe QUEST Experiment on DASI

建议是将QUEST实验部署到南极站，并在两个南方冬季期间运行。接收器和光学器件已经分别获得资金并正在建设中。该望远镜将安装在现有的DASI平台上，使用现有资金支付大部分费用，并重新使用DASI基础设施和控制系统的大部分，这是一个高度杠杆化的建议。QUEST是一个2.6米的卡塞格伦望远镜，配备了下一代偏振敏感辐射热计阵列，旨在以前所未有的灵敏度和角分辨率获得宇宙微波背景（CMB）偏振图。微波背景的极化是由等离子体中性跃迁时物质的大块运动产生的，极化测量是微波背景研究的下一个前沿，它既提供了对标准宇宙学模型进行关键测试的机会，也提供了超越标准宇宙学模型的新见解。微波背景研究中的角尺度通常用球面多极数l来表示，极化模式分解为所谓的e模和b模。DASI是第一个在l ~ 300波段探测e模偏振的实验。最近，WMAP发布了T-E相互关系的结果，延伸到低多极，并提供了关于宇宙再电离的重要新信息。此时，一系列实验正在进行或正在建设中，以改进CMB偏振测量。这里提出的实验（下面称为“QUEST和DASI”，或QUaD）将远远超出这些，是一个真正的“下一代”仪器。QUaD的原始灵敏度与计划中的普朗克太空任务相似，事实上，它们在很大程度上共享相同的技术。然而，当普朗克计划调查整个天空时，QUaD将在极低前景污染的小块区域进行极深的调查。这是两个实验之间的关键区别——不仅仅是QUaD将至少在几年后率先出现。QuaD的地图每像素的信噪比将显著提高。随着灵敏度降低到微开尔文水平，多极率提高到2000甚至更高，这样的地图对于从仪器和前景效应中分离宇宙信号至关重要。这样，预计QUaD地图将与普朗克时代延伸到南极（8米）望远镜上可能的偏振仪和目前正在讨论的CMBpol空间任务相关。就像DASI和CBI在1空间中进行不同范围的互补温度测量一样，BICEP和QUaD将进行互补偏振测量。高多极的b模偏振可以通过干涉大尺度结构的e模模式的透镜得到。QUaD经过优化，可以探测到这种信号，对标准范例进行进一步的关键测试，并限制中微子的质量。暴胀引力波（IGW）会在低一级产生b模信号，此时QUaD开始失去灵敏度，但BICEP在此被优化以探测这个潜在的非常重要的基础物理特征。能达到的对IGW的最终灵敏度将取决于透镜信号可以被去除的程度- QUaD将证明这种拟议技术的可行性。就更广泛的影响而言，现代宇宙学的事业几乎是每个人都能认同的。通过科学，人类可以了解宇宙的起源、性质和命运，这种想法令人着迷，经常出现在报纸和普通杂志上。QUaD的合作者努力通过在正式和非正式场合与公众互动来传达这种兴奋。与该项目相关的外展和教育将通过既定的结构和机制进行传播，例如芝加哥大学宇宙物理中心（CfCP）所实施的结构和机制。这些项目覆盖了当地和遥远的K-12学校的教师和学生，将利用探索宇宙的兴奋来帮助吸引女性和少数民族从事科学研究。研究生和本科生的教育和研究将整合到仪器的建设以及数据的分析中。学生将在项目中扮演主要角色，使他们接触到科学和工程研究的各个方面。他们将学到宝贵的技能，这将有助于他们追求自己的职业生涯，无论是在工业界还是学术界。

The proposal is to deploy the QUEST experiment to the South Pole Station and to operate it over two austral winter seasons. The receiver and optics are already separately funded and under construction. The telescope will be mounted on the existing DASI platform, covering most of the cost of doing so using existing funds, and re-using large parts of the DASI infrastructure and control system, making this a highly leveraged proposal. QUEST is a 2.6-m Cassegrain telescope equipped with a next generation polarization-sensitive bolometer array, which will be aimed on obtaining maps of the Cosmic Microwave Background (CMB) polarization with unprecedented sensitivity and angular resolution. The polarization of the CMB results from bulk motions of material at the time of the plasma-neutral transition and the polarization measurements are the next frontier of CMB research, offering both the opportunity to make crucial tests of the standard cosmological model, and fresh insights which will lead beyond it. Angular scale in CMB studies is customarily referred to by spherical multipole number l, and the polarization pattern decomposed into so-called E-modes and B-modes. DASI was the first experiment to detect E-mode polarization at l ~ 300. More recently WMAP has released results on the T-E cross-correlation extending down to low multipoles and providing important new information on the reionization of the Universe. At this time a battery of experiments are either running or under construction to improve CMB polarization measurements. The experiment proposed here (which is referred below as "QUEST and DASI", or QUaD) will go well beyond these and is a true "next generation" instrument. QUaD has raw sensitivity similar to the planned Planck space mission, and in fact shares much of the same technology. However, while Planck plans to survey the whole sky, QUaD will go extremely deep on small patches selected for extremely low foreground contamination. This is the crucial difference between the two experiments - not simply that QUaD will come first by at least several years. QuaD's maps will have dramatically higher signal to noise per pixel. As the sensitivity is pushed down to microkelvin level and the multipoles up to 2000 and beyond, such maps will prove crucial to disentangling the cosmic signal from instrumental and foreground effects. In this way, it is expected that the QUaD maps will be relevant for extending through the Planck era to that of a possible polarimeter on the South Pole (8-m) Telescope and the CMBpol space mission currently under discussion. In the same way that DASI and CBI make complementary temperature measurements over different ranges in l space, BICEP and QUaD will make complementary polarization measurements. B-mode polarization at higher multipoles is confidently expected from lensing of the E-mode pattern by intervening large-scale structure. QUaD is optimized to detect this signal, making a further crucial test of the standard paradigm and constraining the neutrino mass. Inflationary gravitational waves (IGW) would generate a B-mode signal at lower l, where QUaD begins to lose sensitivity, but where BICEP is optimized to probe for this potentially very important signature of fundamental physics. The ultimate sensitivity to IGW that can be reached will depend on the extent to which the lensing signal can be removed - QUaD will demonstrate the feasibility of this proposed technique. With respect of the broader impact, the enterprise of modern cosmology is one with which almost everybody can identify. The idea that through science humans can understand the origin, nature and fate of our Universe is fascinating, and frequently featured in newspapers and general magazines. QUaD collaborators work hard to communicate this excitement by interacting with the public in both formal and informal settings. Outreach and education related to the project will be disseminated through established structures and mechanisms such as those implemented by the Center for Cosmological Physics (CfCP) at U. Chicago. These programs, which reach out to local and distant K-12 school teachers and students, will use the excitement of exploring our universe to help attract women and minorities to science. Graduate and undergraduate education and research will be integrated in the construction of the instrumentation as well as in the analysis of the data. Students will play a major role in the project, exposing them to all aspects of scientific and engineering research. They will learn valuable skills, which will aid them in pursuing their careers, whether in industry or academia.