Advanced LIGO two-stage twelve-axis vibration isolation and positioning platform. Part 2: Experimental investigation and tests results

• The paper presents near a decade of research on the two-stage twelve-axis vibration isolation platforms developed for Advanced LIGO.
• This system positions and isolates 1000 kg of very sensitive equipment in all directions of translation and rotation.
• The system provides more than three orders of magnitude of isolation over a very large bandwidth.
• We show how results from the prototyping phases have been used for the production and commissioning of 15 units.
• Isolation results show that the system brings the motion below 10−11m/Hz at 1 Hz and 10−12 m/Hz at 10 Hz.

This paper presents the results of the past seven years of experimental investigation and testing done on the two-stage twelve-axis vibration isolation platform for Advanced LIGO gravity waves observatories. This five-ton two-and-half-meter wide system supports more than a 1000 kg of very sensitive equipment. It provides positioning capability and seismic isolation in all directions of translation and rotation. To meet the very stringent requirements of Advanced LIGO, the system must provide more than three orders of magnitude of isolation over a very large bandwidth. It must bring the motion below 10−11 m/Hz at 1 Hz and 10−12 m/Hz at 10 Hz. A prototype of this system has been built in 2006. It has been extensively tested and analyzed during the following two years. This paper shows how the experimental results obtained with the prototype were used to engineer the final design. It highlights how the engineering solutions implemented not only improved the isolation performance but also greatly simplified the assembly, testing, and commissioning process. During the past two years, five units have been constructed, tested, installed and commissioned at each of the two LIGO observatories. Five other units are being built for an upcoming third observatory. The test results presented show that the system meets the motion requirements, and reach the sensor noise in the control bandwidth.

The two-stage vibration isolation and positioning platform (BSC-ISI) provides three orders of magnitude of isolation at all frequencies above 1 Hz.Figure optionsDownload as PowerPoint slide