For the last couple of days we've been trying to find the cause that is preventing us to get more than 0.85 for the arm power.

After re-aligning the reference caivity yesterdau, today I went for the MZ. I slightly changed the alignment of the mirror in pitch. I was able to inrease the MZ-TRANPD to 4.8 (from about 3).

Unfortunately the same increase didn't show up at the MC transmission (that is IFO input) becasue changing the MZ also changed alignment to the MC cavity changed. A little tune of the MZ periscope was necessary to adjust the beam to the MC.

 

After all this MC-TRANS read 7.2 vs 7.0 before: no big of an improvement.

 

The arm power is still below 0.85.

 

Next step: measuring the MC length. Maybe changed a lot after the MC satellite was recently it by the people that were installing sesimometers and accelerometers on it.