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Entry  Thu Mar 15 14:25:05 2018, Craig, DailyProgress, Other, Cavity Power fluctuations vs Temp Fluctuations Screen_Shot_2018-03-15_at_2.53.16_PM.png
    Reply  Thu Mar 15 15:58:02 2018, Craig, DailyProgress, BEAT, Cavity Power fluctuations vs Temp Fluctuations Beatnote_ASD_gpstime_1205189250.pdf
    Reply  Thu Mar 15 18:37:06 2018, Craig, DailyProgress, Other, Cavity Power fluctuations vs Temp Fluctuations NitrogenCylinderRegulatorBefore.jpgWallAirGaugeBefore.jpgNitrogenCylinderRegulatorAfter.jpgScreen_Shot_2018-03-15_at_6.43.59_PM.png
       Reply  Thu Mar 15 22:48:21 2018, Craig, DailyProgress, Other, Cavity Power fluctuations vs Temp Fluctuations 
       Reply  Mon Mar 19 12:10:27 2018, Craig, DailyProgress, Other, Cavity Power fluctuations vs Temp Fluctuations AirSpringPressureRegulator_20180319.jpg
          Reply  Mon Mar 19 13:29:24 2018, awade, DailyProgress, Other, Cavity Power fluctuations vs Temp Fluctuations 
             Reply  Mon Mar 19 14:22:57 2018, Craig, DailyProgress, Other, Cavity Power fluctuations vs Temp Fluctuations NorthAirSpringTubing2.jpgNorthAirSpringTubing.jpg
                Reply  Fri Mar 30 20:12:22 2018, awade, DailyProgress, Other, Disabling the air springs on the vac can: Shimming and clamping 2018-03-30_17.24.30.jpg2018-03-30_17.24.24.jpg
Message ID: 2136     Entry time: Thu Mar 15 14:25:05 2018     Reply to this: 2137   2138
Author: Craig 
Type: DailyProgress 
Category: Other 
Subject: Cavity Power fluctuations vs Temp Fluctuations 

Our initial impression of cavity power fluctuations was that temperature fluctuations in the EAOMs were the cause.  To check this, I made some REFL DC monitors yesterday.
Plotted is one hour of data from today.  Some notes:
1) TRANS DC and REFL DC for both cavites are breathing together every fifteen minutes, and are anticorrelated (one goes up, the other goes down). 
2) The temperature monitors are not fluctuating with the same regularity as the power monitors.
3) The REFL DC for the north PMC is fluctuating with temperature

This leads me to believe our power fluctuations are caused by changes of alignment into the cavities from the air springs holding up our vacuum can. 
Right now, the air springs are hooked up to the wall.  There is probably some pressure regulator which switches on and off every fifteen minutes.  To fix this, I'm going to switch the vacuum air springs over to our nitrogen cylinder we have in the lab and see if the fluctuations go away.

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