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

该计划是将探索实验部署到南极空间站，并在南极站的两个冬季进行操作。接收器和光学设备已经单独出资，并正在建设中。该望远镜将安装在现有的DASI平台上，覆盖利用现有资金这样做的大部分成本，并重新利用DASI基础设施和控制系统的大部分，使这一提议具有很高的杠杆作用。Quest是一台2.6米的卡塞格伦望远镜，配备了新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度分辨率获得宇宙微波背景(CMB)偏振图。CMB的极化是由于等离子体-中性转变时物质的整体运动造成的，偏振测量是CMB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。在CMB研究中，角尺度通常用球面多极数L来表示，偏振态被分解为所谓的E模和B模。DASI是第一个在L~300时探测到E模偏振的实验。最近，WMAP发布了T-E互相关的结果，向下延伸到低多极，并提供了关于宇宙再电离的重要新信息。目前，一系列改善CMB极化测量的实验要么正在进行，要么正在建设中。这里提出的实验(以下称为“QUEST和DASI”，或QUAD)将远远超越这些，是真正的“下一代”仪器。Quad具有类似于计划中的普朗克太空任务的原始敏感性，实际上分享了许多相同的技术。然而，虽然普朗克计划测量整个天空，但Quad将在前景污染极低的小块区域进行极深的探测。这就是这两个实验之间的关键区别--不仅仅是四元组将至少领先几年。Quad的地图每像素信噪比将大幅提高。随着灵敏度下降到微开尔文水平，到2000年及以后，这样的地图将被证明是将宇宙信号从仪器和前景效果中分离出来的关键。通过这种方式，预计四元地图将与通过普朗克时代延伸到目前正在讨论的南极(8米)望远镜上可能的偏振器和CMBpoll空间任务有关。就像DASI和CBI在L空间的不同范围内进行互补温度测量一样，BICEP和QUAD也将进行互补偏振测量。通过干涉大尺度结构对E模模式的透镜，可以肯定地预期在更高的多极子上的B模偏振。QUAD被优化来探测这一信号，对标准范例进行了进一步的关键测试，并限制了中微子的质量。膨胀引力波将在L下方产生一个B模信号，在那里四象限开始失去敏感性，但BICEP被优化以探测这一潜在的非常重要的基础物理特征。能够达到的对IGW的最终灵敏度将取决于可以在多大程度上去除透镜信号--QUAD将证明这项拟议技术的可行性。就更广泛的影响而言，现代宇宙学的事业是几乎每个人都能认同的。通过科学人类可以理解我们宇宙的起源、自然和命运，这一想法很吸引人，经常出现在报纸和普通杂志上。Quad合作者努力通过在正式和非正式环境中与公众互动来传达这种兴奋。与该项目有关的宣传和教育将通过既定的结构和机制传播，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学校的教师和学生，将利用探索我们宇宙的兴奋感来帮助吸引女性和少数族裔进入科学。将把研究生和本科生的教育和研究纳入仪器的建设和数据分析。学生将在这个项目中扮演主要角色，让他们接触到科学和工程研究的方方面面。他们将学习有价值的技能，这将有助于他们追求自己的职业生涯，无论是在工业还是在学术界。

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.