Advanced LIGO subsystems
are the organizational units of the overall project. Follow the links below to view the mission and progress of each subsystem.
|Auxiliary Optics||Core Optics|
|Data Acquisition||Data and|
Fused silica suspension fibers represent a key feature of the Advanced LIGO test mass suspensions. The suspensions are designed to minimise the motion at the test masses due to thermal noise and this is achieved by forming a monolithic final stage in the suspension in which the fibres and test masses are both made of silica - a material with low mechanical loss. To achieve the required seismic isolation the suspension consists of a quadruple pendulum which gives good horizontal isolation, and it incorporates three stages of maraging steel blade springs for vertical isolation. The overall isolation requirement is aimed at achieving a seismic wall at 10 Hz, in conjunction with the seismic isolation (SEI) subsystem to which the suspension is attached. The Advanced LIGO suspension is an extension of the design of the GEO-600 triple pendulum suspensions.
The suspensions form the interface between the seismic isolation subsystem and the suspended optics. As well as providing good passive isolation and low suspension thermal noise, the suspension design provides the means to control the orientation and position of the optic and also to damp the low frequency modes of the suspension. These functions must act without compromising the good thermal and seismic noise performance.
A variety of suspension designs are needed for the main interferometer and input conditioning optics. They are all based on the principle of a multiple pendulum, with two, three or four stages depending on the level of seismic isolation required.
Additional Suspension Photos
Explore Advanced LIGO
Instrumentation and Astrophysics
An Overview of the Upgrades
The International Partnership
LIGO Technology Transfers
LIGO Scientific Collaboration