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Entry  Thu Dec 18 12:52:00 2008, Alberto, Configuration, SUS, Mode Cleaner Cavity Alignment 
    Reply  Thu Dec 18 19:15:54 2008, Alberto, Yoichi, Configuration, SUS, Mode Cleaner Cavity Alignment 
Message ID: 1192     Entry time: Thu Dec 18 12:52:00 2008     Reply to this: 1193
Author: Alberto 
Type: Configuration 
Category: SUS 
Subject: Mode Cleaner Cavity Alignment 
This morning I found the MC locked to the 10 mode. When I locked it on the 00 mode, it was unstable and eventually it always got locked to the wrong mode.

I looked at the Drift Mon MEDM screen, which shows a reference record for position, pitch and yaw of each mirror, and I found that the MC optics were in a different status. Moving the sliders of the mirrors' actuators, I brought them back to the reference position. Then the lock got engaged and it was stable, although the MC reflection from the photodiode, with the wave front sensors (WFS) off, was about 2V. That's higher than the 0.5V the it could get when we aligned the cavity and the input periscope last time.

With the WFS on, the reflection dropped to 0.3V and, so far, the the cavity has been stably locked.
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