40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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Entry  Thu Mar 7 18:12:03 2013, yuta, Update, Alignment, Input beam drift ~ 0.1 mrad/h in pitch IPangulardrift.png
    Reply  Fri Mar 8 20:51:00 2013, Manasa, Update, Alignment, Input beam drift - investigation **IMPORTANT** 
       Reply  Mon Mar 11 12:29:25 2013, Manasa, Update, Alignment, Input beam drift - weekend trend IPANG_drift.png
          Reply  Tue Mar 12 14:02:22 2013, Jenne, Update, Alignment, Beam drift - mystery partially solved? 
Message ID: 8279     Entry time: Tue Mar 12 14:02:22 2013     In reply to: 8267
Author: Jenne 
Type: Update 
Category: Alignment 
Subject: Beam drift - mystery partially solved? 

Steve just told those of us in the control room that the custodian who goes into the IFO room regularly steps on the blue support beams to reach the top of the chambers to clean them.  Since we have seen in the past that stepping on the blue tubes can give the tables a bit of a kick, this could help explain some of the drift, particularly if it was mostly coming from TT2.  The custodian has promised Steve that he won't step on the blue beams anymore.

This doesn't explain any of the ~1 hour timescale drift that we see in the afternoons/evenings, so that's still mysterious.

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