LIGO Document T1500228-v1
- Elastic materials such a metals are described with very good accuracy with linear models. However, material defects can introduce non linear behavior that can be the source of excess noise. One important case is the displacement noise generated by the motion of crystal dislocations (crackling) which can be triggered by the external stress applied to the material. A low frequency variation of the stress can modulate the noise level at much higher frequencies. Such effect may be relevant in the suspension system for the advanced gravitational wave detectors being built.
A dedicated experiment to try to measure this crackling noise is being built, based on a seismically isolated in-vacuum laser interferometer.
The project involves contributions to the assembly and tuning of the suspension system, in particular the implementation of a physical degrees of freedom based suspension damping.
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