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Entry  Mon Mar 16 12:26:59 2009, Yoichi, Configuration, IOO, MC1 drift MC1_Drift1.pdf
    Reply  Tue Mar 17 08:44:37 2009, Yoichi, Configuration, IOO, MC1 drift MC1_Drift3.pdf
Message ID: 1408     Entry time: Tue Mar 17 08:44:37 2009     In reply to: 1406
Author: Yoichi 
Type: Configuration 
Category: IOO 
Subject: MC1 drift 
I'm done with the MC1 drift measurement.
The result is attached. It is clear that MC1 is in trouble. The small drifts in the MC2/MC3 are insignificant compared to the crazy MC1 behavior.
Since there is no drift in the coil feedback voltage monitors, it is probably not a problem of the DACs.
We may be able to fix this by pushing the cables for the MC1 satellite amplifier. But it may require replacement of the coil driver.

There seems to be a large drift of MC1 even when there is no WFS feedback.
The attached plot is an example a 20min trend. You can see that MC1 OSEM signals drift significantly larger than that of MC2/MC3.
You can also be sure that there is no drifting voltage applied to the coils on the MC1 during this period.

If no one is working on the IFO today during the LV meeting, I'd like to leave the MC unlocked and see the trend of the MC1 OSEM signals.
Please do not turn on the MC auto locker unless you want to use the IFO.
If you want to do some measurements, please go ahead and lock the MC, but please write it down in the elog.
Attachment 1: MC1_Drift3.pdf  30 kB  | Hide | Hide all
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