This afternoon, we started to act on the WI CO2 bench, in particular we worked on the preparation  for the acquiaition of  all the needed references before replacing the laser.

The entire procedure is described in https://git.ligo.org/virgo/commissioning/commissioning-tasks/-/issues/73/. 

Here the list of all actions:
1) we switched off the photodiode ISSIN in order to remove the higher part of the plexiglass on the bench

2) we installed a new thermal camera on the BS flange to have another reference (see figure 1).

All references, CH, DAS outer and inner ring have been acquired with the diagnostic system and with the second thermal camera. 

Then, we started to acquire some images of the inner ring and outer ring in some strategical places of the bench with the CCD (Spiricon) (points 1. and 2. in Phase I in the gitlab procedure).
At 19.10 LT, we concluded the activity by restoring the nominal CH and DAS outer ring power injected to the ITF.

Note: we moved two NN sensors  close to the NI bench to avoid to accidentally hit them during the work on the bench.