peter.king@LIGO.ORG - posted 16:52, Thursday 12 March 2015 - last comment - 14:44, Friday 13 March 2015(17235)
LLO Pre-modecleaner
We inspected the input windows of the pre-modecleaner tank. The window in line with the main output beam shows signs of drag wiping. The window in line with the PZT shows signs of damage and some general damage from dust (see attached image). In order to get a better view of the cavity mirrors, we need to pull the pre-modecleaner out of its tank. At the moment it's stuck in the tank after being compressed for over 3 years. Ed, Peter
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I was reminded that at some stage the input windows of the pre-modecleaner were removed and later re-installed, either for use or for shipping. So the window with the photographed damage was most likely the "output" window.
For further notes.
I am 99% certain that the PMC currently being worked on is the LLO "spare". This is the one that degraded quite rapidly and only lasted in the system ~1 month.
The windows were taken off the original PMC and put in the same locations on the spare when it was installed. So window positions as they are on the PMC currently should be where they have been the entire time they have been used.
Here is a reference to an alog about cleaning of the windows of the PMC previously