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Entry  Fri Dec 15 19:09:49 2017, gautam, Update, IOO, IMC lockloss correlated with PRM alignment? PSL_layout.JPG
    Reply  Mon Dec 18 16:45:44 2017, gautam, Update, IOO, IMC lockloss correlated with PRM alignment? 
Message ID: 13486     Entry time: Mon Dec 18 16:45:44 2017     In reply to: 13485
Author: gautam 
Type: Update 
Category: IOO 
Subject: IMC lockloss correlated with PRM alignment? 

I stopped the test earlier today morning around 11:30am. The log file is located at /opt/rtcds/caltech/c1/scripts/SUS/FaradayIsolationTest/PRM_stepping.txt. It contains the times at which the PRM was aligned/misaligned for lookback, and also the number of MC unlocks during every 30 minute period that the PRM alignment was toggled. This was computed by:

  • continuously reading the current value of the EPICS record for MC Trans.
  • comparing its current value to its values 3 seconds ago.
  • If there is a downward step in this comparison greater than 5000 counts, increment a counter variable by 1.
  • Reset counter at the end of 30 minute period.

I think this method is a pretty reliable proxy, because the MC autolocker certainly takes >3 seconds to re-acquire the lock (it has to run mcdown, wait for the next cavity flash, and run mcup in the meantime).

Preliminary analysis suggests no obvious correlation between MC lock duty cycle and PRM alignment.

I leave further analysis to those who are well versed in the science/art of PRM/IMC statistical correlations.

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