Seismic Isolation
25 days ago
- LIGO's extreme sensitivity to vibrations from sources like traffic and earthquakes necessitates advanced vibration isolation to detect gravitational waves, which alter mirror distances by 10^-19 meters.
- Passive isolation uses a quadruple-pendulum system suspending 40kg test masses, with fused silica threads that resist thermal expansion, reducing noise to near-atomic levels.
- Active isolation employs internal seismic platforms with sensors and actuators to counteract ground motions, reducing vibrations to 2x10^-13 meters before passive systems further suppress noise by a million times.