Today, we repeated yesterday's measurements,

To have more flexibility in selecting the aperture diameter, I asked Alessio B. and Angelo E. to prepare a new mask allowing us to switch between two apertures, with diameters of 15 mm and 30 mm.

They managed to manufacture the new mask in just two hours (see Fig. 1). Many thanks to both of them and to the mechanical workshop for their prompt and valuable support!

In the afternoon, we installed the new mask and performed some preliminary checks directly on the actuator, without identifying any anomalies.

We then started the HWS-INJ measurements using the larger, 30 mm diameter aperture. This first measurement was performed during the cooling phase (20261021T1804), which explains the negative OPL variation, appearing in red in the HWS maps (see Fig. 2).

Afterwards, we switched to the smaller, 15 mm diameter aperture.

We then started a second HWS-INJ acquisition, this time during the heating phase (20261021T1928).
The beam appered visible in the HWS map.
At 18.45 UTC, the WI PAM was switched OFF and HWS measurements interrupted.
I left the ITF with arms locked on IR.