this night a large range variation has been observed and it is due to a worsening of the DIFF(+) loop, see Figure 1.
The angular error signals shows a strong instability at 350mHz (to be investigated) while the microseismic noise is more or less stationary.It is worth to be noted that the low frequency worsening of the angular error signal generates a strong worsening of the noise above 10Hz which behaves as timing noise (1Hz harmonics), see Figure 2.
to be investigated
A strong variation in the temperature at the level of NI and WI mirror is visible. Not understood the reason of this increase of temperature
It also interesting to notice the sidebands @ 350mHz around the 50Hz.
This temperature effect is likely induced by the closing of the valves of NI, WI towers during the maintenance break, done for leak test purposes .
The leak tests activity is needed to prepare for the next upgrade: to be coordinated, sorry for the inconvenient
