R&D (FilterCavity)
MarcEisenmann - 18:15, Friday 13 May 2022 (2943)
Recovery of FC (2)

Aritomi, Marc, Michael

 

We installed the new picomotors drivers. They worked fine for PR picomotor but did not work for BS picomotor.

We need to open BS chamber to check the picomotors.

With PR picomotors, we recovered the old reference in BS chamber (eg in elog 2794). In that configuration (and maybe BS in a 'random' position, the green beam is hitting quite below the gate valve window between BS/input but at least we don't have anymore clipping).

However, the PR oplev laser is now hitting the edge of the steering mirror before the PSD. It means that the PR reference at BS chamber that we are using might not be valid anymore for the current alignment inside the PR chamber.

We realigned PR and END oplevs and ran the coil health check codes.

All magnets of PR, INPUT and END mirrors are fine except PR H2 and we can not assess BS situation as the oplev PSD is broken as reported in elog2775.

We found a spare PSD inside the cleanroom and tested its dark noise (see attached figure where red and blue curves are the dark noise).

It is fine so we plan to replace it after the recovery of BS picomotors.

Images attached to this report
2943_20220513130354_11608.jpg