Reducing scattered light in LIGO's third observing run
降低 LIGO 第三次观测运行中的散射光噪声
Noise due to scattered light has been a frequent disturbance in the advanced LIGO gravitational wave detectors, hindering the detection of gravitational waves. The non stationary scatter noise caused by low frequency motion can be recognized as arches in the time-frequency plane of the gravitational wave channel. In this paper, we characterize the scattering noise for LIGO and Virgo's third observing run O3 from April, 2019 to March, 2020. We find at least two different populations of scattering noise and we investigate the multiple origins of one of them as well as its mitigation. We find that relative motion between two specific surfaces is strongly correlated with the presence of scattered light and we implement a technique to reduce this motion. We also present an algorithm using a witness channel to identify the times this noise can be present in the detector.
展开 ▾清晰区分 O3 中慢散射与快散射群体，并把慢散射锁定为 ETM-AERM 与 ETM-TMS 相对运动引起的两种耦合；RC tracking 使散射 glitch 率显著下降，透射光监视器 BLRMS 被证明是比 OSEM 更高效的散射见证通道。
散射光噪声在干涉仪引力波探测器中一直是地面瞬态噪声的重要来源，Accadia+ 2010 在 Virgo 第二次科学运行中识别了散射光噪声，Canuel+ 2013 和 Ottaway+ 2012 给出了背向散射和上转换散射噪声的解析模型。本文把这类分析扩展到 LIGO 第三次观测运行 O3，区分了“慢散射”和“快散射”两个群体，并明确慢散射主要由 ETM 与 AERM、透射光监视器之间的相对运动耦合产生。通过使反应链跟踪主测试质量链（RC tracking），显著抑制 ETM-AERM 散射；对剩余的 ETM-TMS 耦合，作者计划将 TMS 前馈控制用于 O4。在识别工具方面，既有 Zevin+ 2017 的 GravitySpy 图像分类和 Urban+ 2019 的 gwdetchar-scattering，以及 Valdes+ 2017、Longo+ 2020 等基于时频分析的方法；本文提出的透射光监视器带限 RMS 见证通道可直接纳入 gwdetchar-scattering，提高慢散射识别效率。
预印本 2020-07-29 · 接收 2020-11-10 · 刊出 2020-12-14 · 收录 2026-08-20