A Tilt-Free Seismometer for Advanced Gravitational-Wave Detectors

该项目由LIGO研究计划(物理部)和激发竞争研究实验计划(EPSCoR)共同资助。对于正在成熟的引力波物理领域来说，这是一个令人兴奋的时刻。先进的LIGO(激光干涉仪引力波观测站)的建造是对最初的LIGO干涉仪的大修，现已完成，头几个月的数据已经收集完毕。去年，先进的探测器首次直接探测到引力波，这一重大事件将改变我们对宇宙的理解，并标志着引力波天文学新领域的开始。引力波是爱因斯坦在近100年前预测的，它是由大质量天体运动造成的时空扭曲，例如爆炸的恒星和聚合的黑洞或中子星。然而，引力波对时空的影响微乎其微，这就需要设计和建造探测器，以突破精密测量技术的极限。该奖项支持研究，以提高高级LIGO在低频下的灵敏度，并增加探测器收集科学质量数据的时间。此外，该项目将成为本科生和研究生的宝贵培训基地，他们将发展不同学科的科学技能，并为填补学术界和工业界的职位做好准备。该组织坚定地致力于通过在所有层面上的推广与公众分享这一领域的兴奋，特别是在密西西比州的社区。引力波可以通过使用激光测量彼此相距2.5英里(4公里)的镜子之间的距离的微小变化来探测。镜子被悬挂成钟摆，以隔离除引力波以外的所有振动。先进的LIGO探测器已经实现了对反射镜之间距离变化的灵敏度，其灵敏度超过了质子直径的万分之一。然而，要进一步改进干涉仪，以提高引力波探测速度和扩大可观测天体的光谱，仍然存在许多挑战。其中一个挑战来自商业地震仪的设计，这些地震仪用于提供反射镜的主动隔振。地震仪不能区分地面的水平加速度和地面的倾斜。该奖项支持开发高精度无倾斜地震仪，以改善先进的LIGO地震隔离。该项目包括根据各观测站的数据得出对无倾斜地震仪的最新要求，设计和建立仪器模型，建造和测量无倾斜地震仪的性能，并对系统进行理论和实验噪声分析。

This project is jointly funded by the LIGO Research Program (Physics Division) and the Experimental Program to Stimulate Competitive Research (EPSCoR). This is an exciting time for the maturing field of gravitational-wave physics. Construction of Advanced LIGO (the Laser Interferometer Gravitational-wave Observatory), an overhaul of the Initial LIGO interferometers, is now complete and the first couple months of data have been collected. The advanced detectors made last year the first direct detection of gravitational waves, a momentous event that will transform our understanding of the universe and marks the beginning of a new field of gravitational wave astronomy. Predicted by Einstein nearly 100 years ago, gravitational waves are distortions of space-time created by the movements of massive astrophysical objects such as exploding stars and coalescing black holes or neutron stars. The effect of gravitational waves on space-time is minuscule, however, and necessitates the design and construction of detectors that push the limits of precision measurement techniques. This award supports research to improve the Advanced LIGO sensitivity at low frequencies and increase the amount of time the detector is collecting science quality data. In addition, this program will serve as an invaluable training ground for undergraduate and graduate students who will develop scientific skills from a diverse set of disciplines and prepare them to fill positions in academia and industry. The group is strongly committed to sharing the excitement of the field with the public through outreach at all levels, reaching out in particular to the communities in Mississippi.Gravitational waves can be detected by using laser light to measure infinitesimal changes in the distance between mirrors located two-and-a-half miles (4 km) away from one another. The mirrors are suspended as pendulums to isolate them from all vibrations other than the gravitational wave. The Advanced LIGO detectors have achieved a sensitivity to changes in the distance between the mirrors of better than one-ten-thousandth the diameter of a proton. There nonetheless remain many challenges to further improve the interferometers in order to increase the rate of gravitational wave detections and expand the spectrum of astrophysical objects that can be observed. One such challenge arises from the design of the commercial seismometers that are used to provide active vibration isolation of the mirrors. The seismometers cannot distinguish between horizontal acceleration of the ground and tilt of the ground. This award supports the development of a high precision tilt-free seismometer to improve the Advanced LIGO seismic isolation. The project includes deriving updated requirements for a tilt-free seismometer based on data from the observatories, designing and modeling the instrument, constructing and measuring the performance of the tilt-free seismometer and conducting a theoretical and experimental noise analysis of the system.