MRI: Development of a 150 GHz Receiver for the BICEP Array CMB Polarimeter

目前建立的大爆炸理论的宇宙学模型留下了一个开放的问题，即解释整个可观测的宇宙是如何在一个戏剧性的，指数级的“膨胀”中产生的。在这个短暂的暴胀时期之后，宇宙继续膨胀，但速度较慢。人们相信，这种剧烈的时空膨胀会产生现在正在膨胀的宇宙中传播的原初引力波，从而形成宇宙引力波背景（CGB），其振幅测量了暴胀的能量尺度。CGB在宇宙微波背景（CMB）的偏振中留下了一个微弱的签名，检测这种偏振签名可以说是当今宇宙学中最重要的目标。该奖项支持开发150 GHz宽场接收器，用于研究CMB极化，作为BICEP阵列多机构实验的一部分。BICEP阵列继续进行CMB偏振测量的BICEP计划，最终将在30、40、95、150、220和270 GHz的六个频段上工作，以测量和消除银河系的偏振辐射，并探测长期寻找的原始引力波信号。拟议的MRI工作将：（a）在关键的150吉赫频带提供更大的测量能力，因为新的150吉赫接收器将使CMB的测量速度比单一凯克阵列接收器快15倍，代表了在这个频率上的领先测量能力;（B）利用NSF目前在开发BICEP阵列望远镜支架方面的投资，以及其支持BICEP阵列后勤、部署、操作的承诺，（c）利用现有的私人资金建造30/40和95千兆赫接收器，以严格限制拟议的150千兆赫仪器在适当灵敏度水平上的银河同步辐射。这一发展是低风险的，并结合了最近在制造更大的探测器阵列方面取得的重大技术进步。拟议中的BICEP阵列计划是CMB-S4倡议的探路者，旨在建立最终的CMB偏振实验，该实验将结合部署在不同地点的联合收割机许多（多达5-10个）CMB望远镜。

The current established cosmological model for a theory of the Big Bang leaves open the question of explaining how the entire observable Universe being spawned in a dramatic, exponential "inflation" of a sub-nuclear volume. Following this short inflationary period, the Universe continues to expand, but at a less rapid rate. It is believed that this violent space-time expansion would have produced primordial gravitational waves now propagating through the expanding universe, thus forming a cosmic gravitational-wave background (CGB) the amplitude of which measures the energy scale of inflation. The CGB imprints a faint signature in the polarization of the Cosmic Microwave Background (CMB), and detecting this polarization signature is arguably the most important goal in cosmology today. This award supports the development of a 150 GHz wide-field receiver for studying the CMB polarization as part of the BICEP Array multi-institutional experiment. The BICEP Array continues the BICEP program of CMB polarization measurements and will ultimately operate in six frequency bands at 30, 40, 95, 150, 220 and 270 GHz to measure and remove polarized emission from the Milky Way Galaxy and detect the long-sought primordial gravitational waves signal. The proposed MRI effort will: (a) provide a large leap in measurement capability at the critical 150 GHz frequency band as the new 150 GHz receiver will make CMB measurements 15 times more rapidly than a single Keck Array receiver in this band, representing the leading measurement capability at this frequency when fielded; (b) leverage NSF's current investment in developing the BICEP Array telescope mount, and its commitment to supporting BICEP Array logistics, fielding, operations, and data analysis through 2021; and (c) leverage existing private funding to construct 30/40 and 95 GHz receivers that will place tight constraints on galactic synchrotron emission at the appropriate level of sensitivity for the proposed 150 GHz instrument. This development is low-risk and incorporates significant technological advances reached recently with fabrication of larger detector arrays. The proposed BICEP Array program is a pathfinder towards the CMB-S4 initiative to build ultimate CMB polarization experiments, which will combine many (up to 5-10) CMB telescopes deployed at different locations.