LIGO Document T080059-v1

Tilt tests on the RAL noise prototype part 2

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Document type:
T - Technical notes
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12 Feb 2009, 00:09
Part 2: explore the idea that the anomalous tilt seen in the suspensions is a function of hysteresis in the wire at the point where it bends near the wire clamp. Fed the hysteresis model (from T080056) derived from measurements on a single mass into a model of the sus, predicted effects on the sus, compared with measurements, results were compatible.

Notes on work subsequent to this document:
Mark and/or Ken then did some work that convinced us that, given that there are wires only down as far as the penultimate mass, there wold be no effect on observations.

Brett did some very elegant tests on the noise prototype, exciting it and observing the effects using the OSEMs.

Brett and I were able to align the noise prototype using the insights from the work above, especially using the ring-down effect to re-establish a "home" position.

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Notes and Changes:
This is one document of several exploring hysteresis and alignment issues in the quad pendulum. See related documents for the other documents in this study. T080056 is part 1 of this particular study.

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