Advanced LIGO two-stage twelve-axis vibration isolation and positioning platform. Part 1: Design and production overview

• The paper presents the two-stage vibration isolation and positioning platform used in Advanced LIGO gravitational waves detectors.
• The system can support a 1000 kg of sensitive equipment and operate in ultra-high vacuum.
• Each of the two stages provide passive and active isolation in all directions of translation and rotation (12 axis).
• The active control strategy uses a unique combination of relative sensors, geophones and broadband seismometers.
• The system reduces the motion to the level of 10−11 m/Hz at 1 Hz and 10−12 m/Hz at 10 Hz.

New generations of gravity wave detectors require unprecedented levels of vibration isolation. This paper presents the final design of the vibration isolation and positioning platform used in Advanced LIGO to support the interferometer's core optics. This five-ton two-and-half-m wide system operating in ultra-high vacuum. It features two stages of isolation mounted in series. The stages are imbricated to reduce the overall height. Each stage provides isolation in all directions of translation and rotation. The system is instrumented with a unique combination of low noise relative and inertial sensors. The active control provides isolation from 0.1 Hz to 30 Hz. It brings the platform motion down to 10−11 m/Hz at 1 Hz. Active and passive isolation combine to bring the platform motion below 10−12 m/Hz at 10 Hz. The passive isolation lowers the motion below 10−13 m/Hz at 100 Hz. The paper describes how the platform has been engineered not only to meet the isolation requirements, but also to permit the construction, testing, and commissioning process of the fifteen units needed for Advanced LIGO observatories.

The two-stage vibration isolation and positioning platform provides passive and active isolation in all directions and translation. It uses a unique combination of position sensors, geophones and broadband seismometers to provide unprecedented levels of isolation.Figure optionsDownload as PowerPoint slide