aLIGO LHO Logbook

H1 ISC (DetChar)

jenne.driggers@LIGO.ORG - posted 16:39, Wednesday 01 March 2017 - last comment - 18:57, Wednesday 01 March 2017(34507)

Breathing noise ~40-200Hz

Kiwamu reminded me that we started seeing this weird breathing noise between about 40-200Hz just at the beginning of our commissioning time today. We're still not sure what it is, but I've double-checked that everything from commissioning time is put back to nominal positions (PR3 spot position from Kiwamu and Vaishali, ERM positions from Sheila and Heather, and ALS COMM FDD from me (although that shouldn't have anything to do with NomLowNoise) ).

If DetChar or anyone has any thoughts on what this breathing noise might be, that would be helpful. We're starting to run out of ideas....

Comments related to this report

evan.goetz@LIGO.ORG - 17:34, Wednesday 01 March 2017 (34510)

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Could you post the times of these 40-200 Hz breathing mode disturbances? Thank you!

john.zweizig@LIGO.ORG - 18:03, Wednesday 01 March 2017 (34511)

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I believe that the cloud of triggers that can bee seen in the last two hours of the attached plot probably caused by the breathing. At least the frequency range seems right

Images attached to this comment

thomas.shaffer@LIGO.ORG - 18:57, Wednesday 01 March 2017 (34515)

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I cannot comment on times from before my shift, other than what I see on the summary pages, but I can say that it has been this entire lock starting at 23:41 UTC.