[Yuhang, Eleonora]

Today we worked on the recovery of the FC after summer break. We recovered easily the alignment towards the end mirror but once we aligned the input we couldn't find any flash.

Since from the signal we suspected a saturation of the stanford research used to amplify oplev signals in the end, we went to check and we found a major water leakage in the end room.

The floor below and around the vacuum chamber (which is a bit lower with respect to the rest of the room) was completely covered with water (~1cm deep).

While switching on and off the air conditioner we observed that a discrete amount of water started to drop from it along and wall, reaching the floor. We suspect that the drain system of the air condition is not working properly.

We tried to dry the water with some paper but a part of the water is still there. 

Anyway we decided to go on with the recovery: we zeroed the oplev signal, so that the stanford where not saturating anymore and we could close the loop properly. Than we realigned the end mirror, found the flashes and lock the cavity.

To realign the end mirror, we did the usual trick that is to let the beam pass through the second target hole and look for the reflection from the end mirror on the back of the second target. 

Tomorrow we will remove the remaining water and ask Takahashi-san if he can check with us the air conditioner.