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Reports until 14:12, Thursday 21 April 2016
H1 SEI
hugh.radkins@LIGO.ORG - posted 14:12, Thursday 21 April 2016 - last comment - 17:13, Thursday 21 April 2016(26715)
Temperature Excusion at EndY and BRSY Holds on

The Temperature spike at the ENDY did give the BRS a jostle but it seems to have recovered as has the temperature.

The attached trends are 2 days of the BRSY position, velocity,  VEA temp, ground seismo Y, wind and the BRS DRIFTMON.  To me, the most interesting thing is the ring up in the BRS signals near the beginning of the traces likely related to the seismic spike seen.  I suspect this is a VEA entrance that got pretty close to the BRS (stick to the sides if you can rather than the ends of the enclosure.)  This ring up was still not quite enough to trigger the damping so no too bad and you can see how long it takes to ring down without the capacitive damping.

Also, late in the trends, one can see the winds start to pick up and it kicked the BRS enough to trigger the damping--the velocity hit 3000.  Maybe we'll need to bump up the damping threshold??

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Comments related to this report
krishna.venkateswara@LIGO.ORG - 17:13, Thursday 21 April 2016 (26720)

Hugh, you are likely right on both counts. The ring-up was very likely a person going close to the BRS box and yes, the high threshold could be set a bit higher at 4000, to prevent trigerring the capacitive damping during wind-speeds below~35-40 mph.

The ideal solution to this problem would be if we could figure out a way to keep the damping at Q~50 without adding noise. We failed to do this during our trip (see 26596, 26465), most likely because one of the capacitors was shorted, which we realized too late. If we changed the damping scheme it may be possible to have it constantly damped. Worth thinking about more.

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