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

合作研究：使用 DASI 上的 QUEST 实验进行下一代 CMB 偏振测量

• 批准号: 0338238
• 负责人: Clement Pryke
• 金额: $ 91.8万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-15 至 2008-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0338238&HistoricalAwards=false
• 关键词: Collaborative; Research; Next; Generation; CMB

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.

该提议是将 QUEST 实验部署到南极站，并在南极的两个冬季进行运行。接收器和光学器件已经单独资助并正在建设中。该望远镜将安装在现有的 DASI 平台上，使用现有资金承担大部分成本，并重复使用 DASI 基础设施和控制系统的大部分，这使得这是一个高杠杆提案。 QUEST 是一台 2.6 米卡塞格伦望远镜，配备了下一代偏振敏感测辐射热计阵列，旨在以前所未有的灵敏度和角分辨率获取宇宙微波背景 (CMB) 偏振图。 CMB 的极化是由等离子体中性转变时物质的整体运动引起的，极化测量是 CMB 研究的下一个前沿领域，它既提供了对标准宇宙学模型进行关键测试的机会，也提供了新的见解，将引领超越它。 CMB 研究中的角度尺度通常用球面多极数 l 来表示，并且偏振模式分解为所谓的 E 模式和 B 模式。 DASI 是第一个在 l ~ 300 处检测 E 模偏振的实验。最近，WMAP 发布了延伸至低多极的 T-E 互相关结果，并提供了有关宇宙再电离的重要新信息。目前，一系列实验正在运行或正在建设中，以改进 CMB 偏振测量。这里提出的实验（以下称为“QUEST 和 DASI”或 QUaD）将远远超出这些范围，是真正的“下一代”仪器。 QUaD 具有与计划中的普朗克太空任务类似的原始灵敏度，并且实际上共享许多相同的技术。然而，虽然普朗克计划勘测整个天空，但 QUaD 将深入研究前景污染极低的小块区域。这是两个实验之间的关键区别 - 不仅仅是 QUaD 至少会在几年后首先出现。 QuaD 的地图每像素的信噪比将显着提高。随着灵敏度降低到微开尔文水平，多极提高到 2000 甚至更高，这样的图对于将宇宙信号与仪器和前景效应分开至关重要。通过这种方式，预计 QUaD 地图将有助于从普朗克时代延伸到南极（8 米）望远镜上可能的旋光计和目前正在讨论的 CMBpol 太空任务。与 DASI 和 CBI 在 l 空间不同范围内进行互补温度测量的方式相同，BICEP 和 QUaD 将进行互补偏振测量。通过介入大规模结构，E 模式图案的透镜化可以自信地预期更高多极的 B 模式偏振。 QUaD 经过优化来检测该信号，对标准范式进行进一步的关键测试并限制中微子质量。膨胀引力波 (IGW) 将在较低的 l 处产生 B 模式信号，其中 QUaD 开始失去灵敏度，但 BICEP 进行了优化，以探测这一潜在的非常重要的基础物理特征。可以达到的 IGW 最终灵敏度将取决于透镜信号可以消除的程度 - QUaD 将证明该技术的可行性。就更广泛的影响而言，现代宇宙学事业是几乎每个人都能认同的事业。通过科学，人类可以了解宇宙的起源、本质和命运，这一想法令人着迷，并且经常出现在报纸和综合杂志上。 QUaD 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现有的结构和机制进行传播，例如芝加哥大学宇宙物理中心（CfCP）实施的结构和机制。这些项目面向当地和遥远的 K-12 学校教师和学生，将利用探索宇宙的兴奋感来帮助吸引女性和少数族裔参与科学。研究生和本科生的教育和研究将整合到仪器的建造以及数据分析中。学生将在该项目中发挥重要作用，让他们接触到科学和工程研究的各个方面。他们将学习宝贵的技能，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。