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Message ID: 5866     Entry time: Thu Nov 10 20:20:57 2011
Author: Suresh 
Type: Update 
Category: IOO 
Subject: MC Spot positions have shifted after accelerometer installation on MC2 chamber 

[ Jenne, Suresh ]

We were tying the fix the WFS and noticed that the PSL --> MC alignment was poor.   The PMC output was also at about 0.5 instead of its optimal 0.86 .   So Jenne started by first realinging the PMC input and pushed the PMC ouput to about 0.8  

Then we decided to fix the PSL--> MC alignment by using the zigzag.  After Jenne finished that, we realised that it was probably not the best thing to do since the MC2 might have shifted after the accelerometer installation on the MC2 chamber.

So I measured the spot positions and find that the MC2Y has shifted by about 3.6mm and  MC2P has shifted by about a mm.  There is also a shift of 2mm in MC3P, but hopefully it will go away when we adjust the MC2

 

    MC1P MC2P MC3P MC1Y MC2Y MC3Y
03Nov2011   0.1354 -0.2522 -0.1383 -1.0893 0.7122 -1.5587
04Nov2011   4.0411 4.4994 3.5564 -1.4170 -0.2606 -1.7109
08Nov2011   4.7341 4.8794  4.3907 1.3542 -3.0508 -1.7167
10Nov2011 ........ 3.9944 3.7676 6.1001 -1.3058 -3.8087 -1.6418

 

I am going to adjust the MC2 to recover its nominal position as marked above in green

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