This morning, we switched on the new WI CO2 main laser to check for the alignment of the beam on the last optics along the path to the viewport (L5, BS_Rec, HM1): see Fig. 1 for some thermal camera images. Any need of adjusting the rings on the otics.

Then, we re-switched ON the WI CH laser and we checked the heating pattern with the thermal camera from the diagnostic system on the black cardboard - see Fig. 2 for a comparison. From the comparison of the thermal camera images of the DAS OUT taken with the old laser and the new one (see Fig. 3), a misalignment in the horizontal direction is visible.

Just before lunch, around 11 UTC, we closed the bench and re-settled the standard actuator powers (for both CH and DAS) injectd into the ITF. 

The analysis of the images acquired with SPIRICON in the MASK position of the outer ring with old and new laser has been done.

The radius has been estimated by identifyng the inner most intensity isoline for the outer ring (the red circles in fig. 4). The radii have been evaluated through the isoline coordinates after centering the isoline itself.

The thickness has been estimated by performing a Gaussian fit along the vertical and horizontal axes of the ring  geometrical center evaluated before (using the formula a*(x-x0)^2/sigma^2).

The outcomes are summarized in the table below:

The radius of the NEW outer ring is 6% smaller wrt OLD one.
Concerning the thickness, the mean values are within the errors.

In order to undestand if the small outer ring could be an issue for the lock acquisition or for the CARM NULL, in agreement with Michal and Diego, we decided to perform some locking attempts  during the afternoon.
So, Diego restored the CH flip mirrors automation in the lock acqisition code (64764).
Work in progress.

We left:
-WI CH laser ON
-WI main laser ON
-WI main chiller ON
-Guardian system engaged in standard configuration
-NI CO2 lasers (CH and DAS) in standard condition