Seismic isolation and suspension systems for advanced LIGO

N. A. Robertson, C. A. Cantley, N. Lockerbie, LIGO Scientific Collaboration

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

28 Citations (Scopus)
18 Downloads (Pure)


To meet the overall isolation and alignment requirements for the optics in Advanced LIGO, the planned upgrade to LIGO, the US laser interferometric gravitational wave observatory, we are developing three sub-systems: a hydraulic external pre-isolator for low frequency alignment and control, a two-stage active isolation platform designed to give a factor of ~1000 attenuation at 10 Hz, and a multiple pendulum suspension system that provides passive isolation above a few hertz. The hydraulic stage uses laminar-flow quiet hydraulic actuators with millimeter range, and provides isolation and alignment for the optics payload below 10 Hz, including correction for measured Earth tides and the microseism. This stage supports the in-vacuum two-stage active isolation platform, which reduces vibration using force feedback from inertial sensor signals in six degrees of freedom. The platform provides a quiet, controlled structure to mount the suspension system. This latter system has been developed from the triple pendulum suspension used in GEO 600, the German/UK gravitational wave detector. To meet the more stringent noise levels required in Advanced LIGO, the baseline design for the most sensitive optics calls for a quadruple pendulum, whose final stage consists of a 40 kg sapphire mirror suspended on fused silica ribbons to reduce suspension thermal noise.
Original languageEnglish
Title of host publicationProceedings Volume 5500, Gravitational Wave and Particle Astrophysics Detectors
Place of PublicationBellingham, WA USA
Number of pages11
Publication statusPublished - 29 Sep 2004


  • interferometric gravitational wave observatory
  • geo 600 data
  • pendulum suspension system
  • LIGO
  • gravitational waves


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