Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Progress on low-frequency active vibration isolation



S J. Richman


The gravity group at JILA is constructing a three-stage active isolation system to demonstrate useful reduction of low-frequency seismic noise for a gravitational wave interferometer. The control loops on the first two stages are now fully functional in all six rigid-body degrees-of-freedom. Measurements of the responce of the system to large input signals have shown an isolation factor of 3x103 in both vertical and horizontal directions at frequencies of 1 Hz and above. With the most important control system problems solved, we have turned out attention to noise reduction. The first main stage seismometers have been instumented with high-sensitivity readouts. These are single-bounce Michelson interferometers using corner cubes, each illuminated with 1.3 υm light delivered via optical fiber from a quiet Nd:YAG laser. The interfoerometers should allow a shot noise-limited seismometer performance of 3x10-15m/Hz.
Marcel Grossmann Meeting on General Relativity


gravitational waves, LIGO, seismic isolation, seisometers


Richman, S. (2008), Progress on low-frequency active vibration isolation, Marcel Grossmann Meeting on General Relativity (Accessed April 14, 2024)
Created October 16, 2008