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

当前建立的大爆炸理论宇宙学模型留下了一个问题，即解释整个可观测宇宙是如何在亚核体积的戏剧性指数“膨胀”中产生的。在这段短暂的暴胀期之后，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原始引力波，这些引力波现在正在膨胀的宇宙中传播，从而形成宇宙引力波背景（CGB），其幅度可以衡量通货膨胀的能量规模。 CGB 在宇宙微波背景 (CMB) 的偏振中留下了微弱的特征，检测这种偏振特征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 宽视场接收器，用于研究 CMB 偏振，作为 BICEP 阵列多机构实验的一部分。 BICEP 阵列延续了 CMB 偏振测量的 BICEP 计划，最终将在 30、40、95、150、220 和 270 GHz 的六个频段运行，测量和消除银河系的偏振发射，并探测长期寻找的原初引力波信号。拟议的 MRI 工作将： (a) 在关键的 150 GHz 频段提供测量能力的巨大飞跃，因为新的 150 GHz 接收机的 CMB 测量速度比该频段的单个 Keck 阵列接收机快 15 倍，代表了部署时该频率的领先测量能力； (b) 利用 NSF 目前在开发 BICEP 阵列望远镜支架方面的投资，以及到 2021 年支持 BICEP 阵列后勤、部署、操作和数据分析的承诺； (c) 利用现有私人资金建造 30/40 和 95 GHz 接收器，这将对拟议 150 GHz 仪器适当灵敏度水平的银河同步加速器发射施加严格限制。这项开发风险低，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。拟议的 BICEP 阵列计划是 CMB-S4 计划的探路者，该计划旨在建立最终的 CMB 偏振实验，该实验将结合部署在不同地点的许多（最多 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.