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Entry  Fri Oct 28 05:17:13 2011, kiwamu, Update, LSC, locking activity : PZT1 is still railing  
    Reply  Sat Oct 29 05:50:44 2011, kiwamu, Update, LSC, MC suspensions misaligned to avid railing for PZTs MCalignOct282011.pngOct282011.png
Message ID: 5754     Entry time: Fri Oct 28 05:17:13 2011     Reply to this: 5762
Author: kiwamu 
Type: Update 
Category: LSC 
Subject: locking activity : PZT1 is still railing  

Status update on the LSC activity:

 To see how good/bad the beam pointing is, I locked the Y arm with POY11.
Then I ran the ASS servo to automatically correct the alignment of the ITMY and ETMY suspensions and also the beam pointing.
The result is that the PZT1_X is still railing to the negative side.
Due to it the transmitted light from the Y arm is about 0.6 or so which is supposed to be 1 if the beam pointing is perfect.
The EPICS value of PZT1_X is at the minimum of -10 and the ASS servo tried to push it more negative side.
 
 Tomorrow night I will intentionally introduce offsets in the MC suspensions to avoid the railing.
The goal will be a scan of the incident beam while measuring the recycling gain.
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