BICEP阵列BA4-90/150 CMB偏振计的概述与现状
Overview and status of BICEP Array's BA4-90/150 CMB polarimeter
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中文总结 AI 辅助
本文介绍BA4-90/150 CMB偏振计的概况、现状与未来计划，该仪器将部署于南极以搜寻暴胀产生的CMB B模式信号，用于完成BICEP阵列的配置。
中文摘要 AI 辅助
暴胀范式假设早期宇宙存在一段快速膨胀时期，该时期会产生引力波。这些张量扰动会在宇宙微波背景（CMB）的偏振中产生微弱的B模式信号，但该信号比CMB的其他各向异性以及天体物理前景产生的信号弱数个数量级。因此，要对该信号施加更严格的上限或实现确定性探测，除了需要极深的天图外，还需对仪器和测量系统误差进行特殊控制。第四台BICEP阵列接收器BA4-90/150旨在依托该领域领先的小口径CMB实验BICEP系列的技术遗产进行构建与改进，采用二色性仪器在90 GHz和150 GHz波段观测，以推进对暴胀B模式信号的搜寻。该仪器将利用过渡-edge传感器测辐射热计，采用新型两级时分复用系统读出，通过馈源喇叭耦合的正交模式换能器和优化的冷折射光学系统馈电，目标是在现有接收器的基础上提升系统误差控制能力与灵敏度。该仪器计划于2026-27年南极夏季部署到南极，将占据BICEP阵列 mount 中第四个也是最后一个剩余位置，完成Keck Array接收器的逐步淘汰。本文将介绍BA4-90/150接收器的概述，以及其当前状态和未来计划的讨论。
英文摘要
The inflation paradigm postulates a period of rapid expansion in the early Universe, which would generate gravitational waves. These tensor perturbations would produce a faint B-mode signature in the polarization of the cosmic microwave background (CMB), but this signal is orders of magnitude weaker than that from the CMB's other anisotropy and that from astrophysical foregrounds. Placing more-stringent upper limits on this signal or making a definitive detection thus requires exceptional control over instrument and measurement systematics, in addition to extremely-deep maps. The fourth BICEP Array receiver, BA4-90/150, aims to build and improve upon the heritage of the field-leading BICEP series of small-aperture CMB experiments with a dichroic instrument observing in 90 and 150 GHz bands, to advance the search for the inflationary B-mode signal. The instrument will utilize transition-edge-sensor bolometers, which will be read out using a new two-level time-division-multiplexed system and be fed via feedhorn-coupled orthomode transducers and refined cold refractive optics, with the goal of both improving systematics control and sensitivity over existing receivers. With a planned deployment to the South Pole in the 2026-27 austral summer, the instrument will occupy the fourth and final remaining slot in the BICEP Array mount, completing the phaseout of Keck Array receivers. An overview of the BA4-90/150 receiver will be presented, along with a discussion of its current status and future plans for the instrument.
