LIGO Document G1300715-v1
- A 10m arm length prototype interferometer is currently being set up at the AEI in Hannover, Germany. This facility will not only be used for developing novel techniques for future gravitational wave detectors, but furthermore it will provide a platform for high precision experiments such as measuring the standard quantum limit (SQL) of interferometry. To achieve the high requirements on displacement noise for these experiments a very good isolation from seismic motion is required.
Here we present the pre-isolation stage for the 10m prototype interferometer based on a set of passively isolated optical tables. Geometric anti-spring filters provide vertical isolation, attenuation in the horizontal direction is provided by inverted pendulum legs. Several sensors and a Suspension Platform Interferometer will be used to measure the residual table motion. These signals will be used to control the tables at and below their fundamental resonances. Attenuation of more than 60dB below 10Hz was shown in first experiments with purely mechanically passive isolation. Currently two out of three tables are installed in the interferometer vacuum envelope.
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