MRI: Acquisition of a Cryogenic Testbed for Advancing Gravitational-Wave Observation Technology

该奖项支持相对论和相对论天体物理学的研究，并解决了NSF“宇宙之窗”大理念的优先领域。通过发现黑洞和中子星合并产生的引力波，NSF资助的激光干涉引力波天文台（LIGO）打开了一扇了解宇宙的新窗口。但是今天的天文台的灵敏度只够探测引力波天空。LIGO Voyager是一个潜在的升级，以最大限度地发挥LIGO设施的潜力，而Cosmic Explorer是一个40公里基线的下一代美国概念，将极大地扩大人类对引力宇宙的访问，并通过利用先进技术观察所有恒星大小的黑洞合并，主要是在非常低的温度下操作的晶体硅光学。这些天文台的低温操作面临的主要挑战包括：制造具有优异光学性能的大型纯硅晶体;识别高质量的光学涂层;以及将光学器件保持在稳定的低温下。该项目将支持购买一个灵活的低温试验台，使加州州立大学富勒顿的研究人员能够解决其中一些挑战，特别是那些关于硅和涂层的光学特性以及温度和振动控制的挑战。此次收购将为主要本科和西班牙裔服务机构的一代学生提供实践低温硬件的机会：CSUF和附近的社区学院（通过既定的研究计划）。此次收购所带来的科学成果将为宇宙探测器的设计做出重要贡献，同时为现有设施的潜在升级提供信息，从而扩大引力波科学的发现空间。LIGO Voyager和Cosmic Explorer将深入引力宇宙，达到每小时数十次的观测速率，数千次的信噪比，并观测所有中子星星和恒星质量黑洞的合并。使用低温晶体硅光学器件和悬架来降低噪音是旅行者号和宇宙探测器的基石。硅在123 K时具有零热膨胀，消除了光吸收引起的热弹性噪声和热畸变，并且较低的温度降低了热振动。这些光学器件的低温操作的关键挑战包括：制造具有低光学散射和吸收的大的纯硅晶体;识别具有优异光学和材料特性的光学涂层;以及将光学器件无声地保持在目标温度。该项目将支持收购一个灵活的低温试验台，使加州州立大学富勒顿能够应对这些挑战，特别是光学特性和温度和振动控制的涂层硅光学。此次收购将使晶体硅光学器件、晶体AlGaAs/GaAs涂层以及非晶硅和二氧化硅涂层的材料和光学特性研究成为可能，这些都是光学和材料界感兴趣的领域。它将为主要本科和西班牙裔服务机构的一代学生提供实践低温硬件的机会：CSUF和附近的社区学院（通过既定的研究计划）。此次收购所取得的科学成果将为宇宙探索者的设计做出重要贡献，同时为现有设施的潜在升级提供信息，从而扩大引力波科学的发现空间。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports research in relativity and relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. By discovering gravitational waves from merging black holes and neutron stars, the NSF-funded Laser Interferometer Gravitational-Wave Observatory (LIGO) has opened a new window on the universe. But today’s observatories are only just sensitive enough to probe the gravitational-wave sky. LIGO Voyager, a potential upgrade to maximize the potential of the LIGO facilities, and Cosmic Explorer, a 40km baseline next-generation US concept, would greatly expand humanity’s access to the gravitational universe and observe all star-sized black hole mergers, by leveraging advanced technologies, chiefly crystalline silicon optics operated at very low (cryogenic) temperatures. Key challenges for the cryogenic operation of these observatories include: fabricating large, pure silicon crystals with excellent optical properties; identifying high-quality optical coatings; and noiselessly holding the optics to stable low temperatures. This project will support the acquisition of a flexible cryogenic testbed to enable researchers at California State University Fullerton to address some of these challenges, particularly those regarding optical properties of the silicon and coatings and temperature and vibration control. This acquisition will provide opportunities for hands-on experience with cryogenic hardware to a generation of students at primarily undergraduate and Hispanic-serving institutions: CSUF and nearby community colleges (through established research programs). Scientific results made possible by this acquisition will expand the discovery space of gravitational-wave science by making essential contributions to the design of Cosmic Explorer while informing potential upgrades to current facilities.LIGO Voyager and Cosmic Explorer would peer deep into the gravitational universe reaching observation rates of tens per hour, signal-to-noise ratios in the thousands, and observing all neutron star and stellar-mass black hole mergers. The use of cryogenic crystalline silicon optics and suspensions to reduce noise is a cornerstone for Voyager and Cosmic Explorer. Silicon has zero thermal expansion at 123 K, eliminating thermoelastic noise and thermal aberrations from light absorption, and the lower temperature reduces thermal vibrations. Key challenges for the cryogenic operation of these optics include: fabricating large, pure silicon crystals with low optical scattering and absorption; identifying optical coatings with excellent optical and material properties; and noiselessly holding the optics to target temperatures. This project will support the acquisition of a flexible cryogenic testbed to enable California State University Fullerton to address these challenges, particularly optical characterization and temperature and vibration control of coated silicon optics. The acquisition will enable research on the material and optical properties of crystalline silicon optics, crystalline AlGaAs/GaAs coatings, and amorphous silicon and silica coatings, each of interest to the optics and materials communities. It will provide opportunities for hands-on experience with cryogenic hardware to a generation of students at primarily undergraduate and Hispanic-serving institutions: CSUF and nearby community colleges (through established research programs). Scientific results made possible by this acquisition will expand the discovery space of gravitational-wave science by making essential contributions to the design of Cosmic Explorer while informing potential upgrades to current facilities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.