R&D (FilterCavity)
MarcEisenmann - 19:24, Monday 23 May 2022 (2952)
investigation about input oplev

Marc, Michael, Yuhang (remote)

It was reported in elog 2828 that input oplev spectra are similar for pitch and yaw.

First we wanted to realign input oplev but found out that diaggui was timed out.

This can be fixed by restarting the standalone pc.

Before that, we need to take a snapshot of the medm configuration but the disk was almost full (99%). In the past, this prevented proper snapshot (eg in elog 2881) so we deleted the data from the disk beforehand.

We followed procedure from elog 1979 where the delete command is rm -r 13*** to delete all files starting with 13. We removed all trend/second and full data of May that freed 7% of storage.

After that we could investigate the input oplev behavior.

We found out that there is now only one SR560 (the other one is in ATC cleanroom for the new OPO test setup).

In that case, only pitch is increased by a factor of 100 and we guess that the yaw signal is somehow normalized by the sum (effectively pitch) making the 2 signals identical.

When removing the SR560 connection, we could see the expected mechanical resonances of pitch and yaw.

Note that now x is yaw and y is pitch.

Because we will not replace the OPO so soon, we plan to take back the SR560 from ATC to the input oplev.