LIGO Document E1400353-v1

ECR: Beam Diverter Lubrication and Balance

Document #:
LIGO-E1400353-v1
Document type:
E - Engineering documents
Other Versions:
Abstract:
It has been noticed (LLO Log 14230) that the ruby bearings on the aLIGO beam
diverter (D1100642) have an unpredictable and relatively large amount of
friction. This excess friction frustrates efforts to balance the side-to-side
motion of the beam diverter. The bearing friction is very effectively
mitigated by a tiny addition of a low vapor pressure Krytox LVP lubricant, as was
demonstrated during the LLO ETM-X vent in August 2014. Unfortunately, the
resulting low bearing friction exposes the next layer of problem in that the
balancing was not sufficient to permit symmetric operation of the diverter from
one extreme of motion to the other. The solution to this is to rebalance the
diverter once the friction has been reduced by lubrication.

Refer to bug 934 i.e. https://services.ligo-wa.caltech.edu/integrationissues/show_bug.cgi?id=934.

As above also refer to LLO alog 14230 https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=14230.

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Keywords:
diverter
Notes and Changes:
26th August 2014. Approval given for this ($0 parts) ECR. Drawings and procedure linked should be updated and released via DCN. ALL spares at both sites should be assembled, tested and modified. A brief summary should be posted and linked to this ECR and to to bug 934. Final decision on when to fix in chamber assemblies will be determined via bugzilla, specifically bug 934, see link above. Calum Torrie
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