Modeling Cable Noise in LIGO

Document #:

LIGO-T0900083-x0

Document type:

T - Technical notes

Abstract:

The Laser Interferometer Gravitational-Wave Observatory (LIGO) has test masses and optics hung as the bottom mass on simple pendula in order to isolate them from the motion of the Earth. In Advanced LIGO, optics will be hung on multistage pendula to increase isolation. However, cables need to be attached to sensors and actuators on some of these pendula, which can potentially degrade the vibrational isolation and change the dynamics of the system. To understand the effects of the cabling, we used Mathematica to model the cables as collections of small masses connected by springs. With our model, we can quickly and easily look at how the cables affect the pendula, once we have experimentally determined a few of their physical parameters.

Files in Document:

None

Topics:

• Suspensions
• Final Design
• Modelling

Authors:

• Julian Earl Freed-Brown

Keywords:

cables suspensions OMC

Notes and Changes:

Initial version.